The rate at which a company pays corporation tax depends on the level of its taxable profits. Where a company’s profits are below the lower profits limit, corporation tax is charged on all profits at the rate of 19% and where a company’s profits are more than the upper profits limit, they are all taxed at the rate of 25%. However, where the profit falls between these limits, corporation tax is charged at the rate of 25% and reduced by marginal relief. The effect of this is to provide a gradual increase in the rate of corporation tax from the small profits rate to the main rate.

For the financial years 2024 and 2025, the lower profits limit is £50,000 and the upper profits limit is £250,000. Where a company has one or more associated companies, these limits are divided by the number of associated companies plus one, so if a company has one associate, the limits are, respectively, £25,000 and £125,000. The limits are also proportionately reduced where the accounting period is less than 12 months.

Marginal relief is calculated by reference to the following formula:

F x (U – A) x N/A

Where:

F is the marginal relief fraction;

U is the upper profits limit;

A is the augmented profits for the accounting period; and

N is the total taxable profits for the accounting period.

The marginal relief fraction for the financial year 2025 is 3/200, unchanged from the financial year 2024.

Augmented profits are the company’s total taxable profits plus qualifying exempt distributions received by the company which are not excluded. Qualifying exempt distributions include dividends, distributions of assets, amounts treated as a distribution on the transfer of assets and liabilities and bonus issues following a repayment of share capital. Distributions are excluded from the calculation of augmented profits if they are from a 51% subsidiary, a company of which the recipient is a 51% subsidiary or a trading company or relevant holding company that is a quasi-subsidiary of the recipient.

If the company has no qualifying exempt distributions to take into account, augmented profits are the same as taxable profits and the formula can be simplified to F x (U – A).

To make things easier, HMRC have produced a tool which can be used to work out marginal relief. This can be found on the Gov.uk website at www.tax.service.gov.uk/marginal-relief-calculator.

Example

A Ltd prepares accounts to 31 March each year. For the year to 31 March 2025, it had taxable profits of £80,000. It does not receive any qualifying exempt distributions. Consequently, its augmented profits are also £80,000.

The company’s marginal relief is calculated as follows:

3/200 x (£250,000 – £80,000) x 1 = £2,550.

At the main rate, the company would pay corporation tax of £20,000 on its profits (£80,000 x 25%).

The company’s corporation tax bill is therefore £17,450, being corporation tax at the main rate of 25% (£20,000) as reduced by the marginal relief of £2,550.

The company’s effective rate of corporation tax is 21.81%.

A taxpayer may have grounds for appealing a penalty if they have a reasonable excuse for missing a filing or payment deadline. However, it is important to realise that the appeal will only succeed if HMRC accept that the excuse is indeed reasonable. In this regard, the bar is set high.

The first point to note is that there is no statutory definition of ‘reasonable excuse’. Whether a person has a reasonable excuse depends on the circumstances in which the failure to meet the obligation occurred, as well as the circumstances and the abilities of the person who failed to meet the obligation. Consequently, what might be a reasonable excuse for one person may not be a reasonable excuse for someone else.

HMRC’s approach

In determining whether an excuse is ‘reasonable’, HMRC’s approach is to look at what a reasonable person with the same attributes and abilities who wanted to comply with their tax obligations would have done in the same circumstances. A reasonable excuse is one that stops a taxpayer from meeting their obligations for a valid reason. In guidance published on the Gov.uk website, HMRC provide the following examples of reasons for a failure to comply which may be accepted as constituting a reasonable excuse:

• The taxpayer’s partner or a close relative died shortly before the tax return or payment deadline.
• The taxpayer had an unexpected stay in hospital which prevented them from dealing with their tax affairs.
• The taxpayer had a serious or life-threatening illness.
• The taxpayer’s computer or software failed while they were preparing their return online.
• The taxpayer experienced issues with HMRC’s online services.
• The taxpayer was prevented from completing their tax return because of a flood, a fire or a theft.
• The deadline was missed due to postal delays which the taxpayer could not have predicted.
• The delay related to a disability or a mental illness which the taxpayer has.
• The taxpayer was unaware of or misunderstood their legal obligations.
• The taxpayer relied on someone else to do their return and they failed to do so.

Where the taxpayer has a reasonable excuse for missing a filing deadline or making a payment, they should rectify this as soon as they are able.

Unacceptable excuses

Like ‘the dog ate my homework’, HMRC do not accept the following excuses as providing a valid reason for missing a filing deadline or failing to make a payment on time:

• A cheque or payment bouncing because the taxpayer did not have enough money in their account.
• Finding the HMRC system too difficult to use.
• Missing the deadline because a reminder was not received from HMRC.
• A mistake was made on the tax return.

The normal filing deadline for the 2024/25 Self Assessment tax return is 31 January 2026. However, if you have some tax to pay under Self Assessment and you also pay tax under PAYE, if you file your return by 30 December 2025, you may be able to pay what you owe through an adjustment to your tax code rather than through the Self Assessment system. This may be the case if, for example, you are employed or receive a pension and also have some income from self-employment or property or you have taxable investment income.

Conditions

Tax due under Self Assessment can only be collected through your tax code if the following conditions are met:

• the total amount that you owe through Self Assessment is £3,000 or less;
• you already pay tax through PAYE (for example, because you are employed or receive a company pension); and
• you filed a paper return by 31 October 2025 or an online return by 30 December 2025.

It should be noted that if the amount you owe is more than £3,000, you cannot make a part payment to reduce the outstanding amount to £3,000 or less and pay the balance through your tax code.

However, even if these conditions are met, you will not be able to pay your Self Assessment tax bill through your tax code if any of the following apply:

• you do not have sufficient PAYE income to collect the amount that is due;
• you would end up paying more than 50% of your income in tax; or
• you would end up paying over twice as much tax as you normally do.

How it works

If you have filed your return by the deadline and you are eligible to pay your tax bill through your tax code, HMRC will automatically adjust your tax code to collect the amount of tax that you owe, unless you indicate that you do not wish to pay your tax in this way. The adjustment will take the form of a deduction from your allowances. The amount of the deduction will depend on how much you owe and your marginal rate of tax. For example, if you pay tax at 40% and owe tax under Self Assessment of £1,000, your allowances will be reduced by £2,500 (40% of £2,500 = £1,000).

The adjustment will be made to your 2026/27 tax code. As a result of the adjustment, you will pay what you owe for 2024/25 in equal instalments throughout 2026/27 each time that you are paid. If you are paid monthly, you will effectively pay your bill in 12 monthly instalments.

Advantages and disadvantages

Paying tax through your tax code allows you to pay it later – instead of having to settle the bill by 31 January 2026, you pay it in equal instalments over the 2026/27 tax year. This provides a cashflow benefit and removes the need to find the funds to pay the bill in one hit.

Paying your bill through your tax code also provides an automatic interest-free instalment plan. Unlike a Time to Pay arrangement, you do not need to set it up, and there is no interest to pay either.

However, having your tax deducted from your pay will reduce your take-home pay, so it may not be for everyone.

If you are new to Self Assessment and need to submit a tax return for 2024/25, you will need to register for Self Assessment. This should be done before 5 October 2025 in order to avoid a penalty and to ensure that you receive your Unique Taxpayer Reference (UTR) and Notice to File in good time. You can either register for Self Assessment yourself or appoint an agent to register on your behalf.

If you register after 5 October 2025, you may receive a failure to notify penalty.

Check whether you need to register

You may need to register for Self Assessment if you do not currently complete a Self Assessment tax return and you had a new source of untaxed income in 2024/25. This may be the case if you started a new trade, which may include a side hustle in addition to your employment, or you started renting out property, either on a long-term let or as holiday accommodation.

However, even if you have a new source of untaxed income, you will not necessarily need to register. This will be the case if, for example, all your income from self-employment (before deductions) is less than £1,000 in the 2024/25 tax year or if your property rental income is less than £1,000 in the tax year. If you let a furnished room in your own home, there is no need to register if your rental income is less than the rent-a-room limit (£7,500 where one person receives the income or £3,750 each where more than one person receives the income).

You can check if you need to send a return by using the tool on the Gov.uk website at www.gov.uk/check-if-you-need-tax-return.

Registered before

If you have previously registered for Self Assessment but did not file a return for 2023/24, you will need to sign into the Government Gateway to reactivate your account. If you are unable to do this, you can instead complete form CWF1 and send this to HMRC.

Register online

If you need to register for Self Assessment, you can do so online by visiting the Gov.uk website at www.gov.uk/register-for-self-assessment. It can take up to  21working days for your registration to be confirmed.

File your return

The deadline for filing your 2024/25 Self Assessment tax return online is midnight on 31 January 2026. Once registered, you can file your return – you do not need to wait until January. If you miss the deadline, you will receive a late filing penalty of £100.

If you did not receive your Notice to File a return until after 31 October 2025 (but you registered for Self Assessment on or before 5 October 2025), you have until three months from the date on the Notice to File in which to file your return.

Pay your tax

You must pay any tax owing for 2024/25 by 31 January 2026. If your tax bill for 2024/25 was more than £1,000, unless 80% of your tax bill for the year was collected at source (such as under PAYE), you will also need to make the first payment on account of your 2025/26 tax liability by the same date. This is 50% of your Self Assessment tax and Class 1 National Insurance bill for 2024/25.

A Simple Assessment is used for taxpayers with very straightforward tax affairs. A taxpayer may receive a Simple Assessment letter from HMRC if they owe income tax that cannot be taken out of their income automatically, they owe HMRC more than £3,000 or they have tax to pay on their state pension. A person may also receive a Simple Assessment letter if they have tax to pay on their bank or building society interest.

A Simple Assessment letter will be sent by post and, where the taxpayer has a personal tax account, to their personal tax account. The letter will show the person’s taxable income, such as that from employment income, a state pension or investments, any income tax that they have already paid (for example, under PAYE) and the balance that they owe.

If you receive a Simple Assessment letter, it is important that you check that the figures shown on it are correct. For example, you can check that the figure for your employment income matches that shown on your P60. If you do not agree with the figures shown or the calculation, you should contact HMRC within 60 days of the date on the letter.

If you receive a Simple Assessment but you complete a Self Assessment tax return, you should contact HMRC (on 0300 200 3300) within 60 days of the date of the letter to get the Simple Assessment withdrawn.

Paying the bill

The deadline for paying a Simple Assessment bill depends on the date on which the letter is received. If a Simple Assessment letter for 2024/25 is received before 31 October 2025, the tax owing must be paid by 31 January 2026. However, if the letter is not received until after 31 October 2025, the tax must be paid within three months of the date on the letter.

The tax due can be paid online, by bank transfer or by cheque.

Help to pay

Taxpayers who will struggle to pay their Simple Assessment bill by the due date can now spread the cost and pay in instalments by setting up a Time to Pay arrangement. A taxpayer can set up a Simple Assessment payment plan online if they owe between £32 and £50,000 and do not have any other payment plans or debts with HMRC.

Taxpayers within Simple Assessment who want to pay in instalments but are not able to set up a plan online will need to contact them to see if they can agree an instalment plan with them.

Where an instalment plan is agreed, interest is charged on tax paid after the due date, but there are no late payment penalties.

Businesses must register for VAT when their turnover exceeds the registration threshold (currently £90,000). This must be done if, at the end of any month, the taxable supplies in the previous 12 months or less exceed the registration threshold or if the business expects that in the next 30 days alone their turnover will exceed the registration threshold.

Businesses whose turnover does not reach the threshold do not need to register; however, they may choose to do so voluntarily. This can be advantageous, for example, if they make zero-rated supplies but buy goods or services which are liable for VAT at the standard or reduced rate as it will enable them to recover the VAT suffered.

Start date

When a business registers for VAT voluntarily, they can choose the date from which their VAT registration takes effect. It is important that this date is chosen carefully as once the VAT registration is effective, the business can recover VAT incurred from that date but must also charge VAT on taxable supplies that it makes from that date. It is not possible to recover VAT incurred on purchases prior to the date of registration, so if the business is planning a large purchase on which they hope to recover the VAT, they should ensure that their VAT registration is effective before making the purchase.

A business can apply for their voluntary registration to be backdated by up to four years from the date that they register for VAT. Where the registration is backdated, the business will be able to recover VAT charged on taxable supplies from that date. On the flip side, the business must also account for VAT at the correct rate on all taxable supplies made on or after that date.

Amending the registration date

It is important that businesses voluntarily registering for VAT consider carefully when they want their registration to take effect as there is no automatic right to change it and there is no right of appeal if HMRC deny a request to amend the effective date of registration. Where a mistake is made in choosing the effective date of registration and this affects the pre-registration cost calculations of what the business can recover and what the business must account for, HMRC will not normally allow the registration date to be changed.

Individuals who claim higher or additional rate relief for personal pension contributions through their tax code may now need to provide evidence in support of their claim where previously they did not need to do so. HMRC changed the rules as regards the provision of supporting evidence with effect from 1 September 2025. From the same date, HMRC ceased accepting claims by telephone; claims now must be made online or by letter.

Taxpayers who complete a Self Assessment tax return must make their claim in their tax return rather than by this route.

Eligibility

A person is eligible to claim relief if they pay tax at a rate higher than the basic rate, for example, at the higher or additional rate or, in Scotland, at the intermediate rate or above, and pay into a pension scheme where they receive tax relief at the basic rate of tax. Basic rate taxpayers who pay into a workplace pension scheme where the employer does not or will no longer claim tax relief can also make a claim, as can basic rate taxpayers who pay a lump sum into a personal or workplace pension where the scheme is not a net pay scheme (i.e. one where pension contributions are deducted from gross pay).

Information required

In order to make a claim, the claimant will need the following information:

• their National Insurance number;
• the type of pension that they have;
• the name of their pension provider;
• the net amount of pension contributions for each tax year in respect of which they are claiming tax relief; and
• their payroll number or reference (where applicable).

Supporting evidence

The claimant will also now need to provide evidence in support of their claim for each tax year for which relief is claimed. The evidence could be in the form of a letter or statement from their pension provider or a pay slip from their employer. It must include:

• the claimant’s full name;
• details of pension contributions paid in the tax year to which the claim relates; and
• where the claim relates to a workplace pension, evidence that they have received basic rate relief (20%) automatically from their employer.

Making a claim

HMRC prefer claims to be made online. This can be done by visiting the Gov.uk website (see www.gov.uk/guidance/claim-tax-relief-on-your-private-pension-payments). Where the claimant is unable to claim online or the claim is made by an agent on the claimant’s behalf, the claim should be made by letter. The information and evidence set out above should be included with the letter.

HMRC should contact the claimant within 28 working days.

Claims can be amended once submitted, for example, to provide details of another pension. Where the claim was made online, the claim details can be amended online. If the claim was made by letter, the taxpayer must send a further letter setting out details of the changes.

A VAT invoice is an invoice that contains information required by the VAT regulations. A VAT invoice can only be issued by a business which is registered for VAT. Where a business is VAT registered, they must issue a VAT invoice whenever they supply goods or services that are liable to the standard rate of VAT or a reduced rate to another taxable person. A VAT invoice must normally be issued within 30 days of the date on which the supply was made.

VAT invoices are important and the business must keep a copy of every VAT invoice that they issue. Likewise, they must keep a copy of every VAT invoice that they receive. VAT invoices are the primary evidence of VAT charged and VAT incurred.

Details that must be included

Every VAT invoice issued must include the following information:

• a sequential number based on one or more series that uniquely identifies the document;
• the time of supply;
• the date of issue of the document (where this is different from the time of supply);
• the name, address and VAT registration number of the supplier;
• the name and address of the person to whom the goods  or services are supplied;
• a description sufficient to identify the goods or services supplied;
• for each description, the quantity of the goods or the extent of the services, and the rate of VAT and the amount payable, excluding VAT, expressed in any currency;
• the gross total amount payable, excluding VAT, expressed in any currency;
• the rate of any cash discount offered;
• the total amount of VAT chargeable, expressed in sterling; and
• the unit price.

It should be noted that different rules apply where a margin scheme is used and the business should follow the rules of the scheme.

Where a business based in Northern Ireland sends an invoice to a person in an EU member state, the VAT invoice must also include the letters ‘GB’ in front of the VAT registration number for cross-border supplies, the registration number of the recipient preceded by the alphabetical code for the relevant EU member state and a reference to the means of transport.

Electronic invoices

VAT invoices may be issued electronically, and electronic invoices offer a number of advantages over paper invoices. Electronic invoicing is the transmission and storage of invoices in an electronic format without duplicate paper invoices.

The information set out above in relation to paper invoices must also be contained in electronic invoices. However, when sending batches of invoices to the same customer, information that is common to the individual batches may be recorded once per batch rather than on each invoice. For example, the customer’s full name could be included on the batch header rather than on each individual invoice.

Retail invoices

There is no requirement to issue a VAT invoice for retail supplies to unregistered businesses. If asked for a VAT invoice and the supply is £250 or less, a simplified VAT invoice can be issued. However, if the supply is more than £250, a full VAT invoice must be provided if requested.

Simplified invoice

A simplified invoice can be issued if the supply is £250 or less showing the supplier’s name, address and VAT registration number, the time of supply, a description of the goods or services and the VAT rate charged for each, the total amount payable including the VAT shown in sterling and the VAT rate charged. Exempt supplies should not be included in a simplified invoice.

Where the value of the supply is more than £250, a full VAT invoice must be issued.

Credit notes

Where a credit note is issued, it must include the same information as the original invoice and sufficient information to identify the original invoice.

Currency

Although the invoice amounts may be expressed in any currency, where there is a positive rate of VAT due in the UK, the total amount of VAT must be expressed in sterling.

There are various ways in which profits can be extracted from a personal or family company. A popular and tax-efficient extraction strategy is to pay a small salary and to extract further profits as dividends as long as the company has sufficient retained profits.

One of the advantages of paying a salary is to secure a qualifying year for state pension and benefit purposes. A person needs 35 qualifying years when they reach state pension age to receive a full state pension and at least ten qualifying years to receive a reduced state pension. If the director does not yet have 35 qualifying years, it is worth paying a salary which is sufficient for the year to be a qualifying year.

A year will be a qualifying year if an individual has qualifying earnings subject to National Insurance that are at least 52 times the lower earnings limit. Payments of salary and bonus are liable to Class 1 National Insurance. By contrast, dividends do not attract National Insurance.

For 2025/26, the lower earnings limit is set at £125 per week. Thus, it is necessary to pay a salary or bonus of at least £6,500 (52 x £125) for the year to be a qualifying year.

Where earnings are between the lower earnings limit and the primary threshold, which for 2025/26 is aligned with the personal allowance at £12,570, primary contributions are payable at a notional zero rate. This means that the director or employee benefits from a qualifying year for state pension purposes without having to actually pay any primary Class 1 National Insurance contributions.

However, the same is not true for the employer. The reduction in the secondary threshold to £5,000 from 6 April 2025 means that the secondary threshold is now below the lower earnings limit and, unless the employment allowance is available to shelter employer contributions, paying a salary equal to the lower earnings limit will come with a secondary Class 1 National Insurance bill.

Personal companies where the sole employee paid above the secondary threshold is also a director do not benefit from the employment allowance. Consequently, where a salary is paid which is of a level which is sufficient for a year to be a qualifying year for state pension purposes, secondary contributions will be payable. On a salary of £6,500 (the minimum needed for a qualifying year), the associated secondary Class 1 National Insurance bill will be £225 (15% (£6,500 – £5,000)).

In a family company where the employment allowance is available, it is possible to pay a salary which is sufficient to secure a qualifying year without an associated secondary Class 1 liability.

Although it is only necessary to pay a salary of £6,500 for the year to be a qualifying year for state pension purposes, if the personal allowance is available in full, it is more tax efficient to pay a salary of £12,570, as the corporation tax deduction on the salary and secondary Class 1 National Insurance will outweigh the secondary Class 1 National Insurance bill.

The liability for self-employed earners to pay Class 2 National Insurance contributions was abolished with effect from 6 April 2024. Now Class 2 National Insurance is a voluntary charge which self-employed earners with profits below the small profits threshold can choose to pay to secure a qualifying year for state pension and benefit purposes. Where a self-employed earner has profits in excess of the small profits threshold, they receive a National Insurance credit if their profits are between the small profits threshold and the lower profits threshold. If their profits exceed the lower profits limit, they will pay Class 4 contributions.

For 2024/25, Class 2 contributions are only payable where a self-employed earner has profits below the small profits threshold (which for 2024/25 is £6,725) and they have opted to pay Class 2 voluntarily. For 2024/25, voluntary Class 2 contributions are payable at the rate of £3.45 per week; an annual liability of £179.40.

The problem

Some self-employed taxpayers have been charged Class 2 National Insurance contributions for 2024/25 in error. The nature of the error depends on their particular circumstances. Some self-employed earners with profits in excess of the lower profits limit (set at £12,570 for 2024/25) have had a Class 2 National Insurance charge of £358.80 added to their account. This is twice the voluntary Class 2 charge for 2024/25. Self-employed earners with profits in excess of £12,570 are liable to pay Class 4 National Insurance on their profits only.

In some cases, the amount added in error is less than £358.80.

Resolving the issue

HMRC have stated that they have taken action to correct the error where the information that they hold has enabled them to do so. Some self-employed taxpayers have also reported that their Self Assessment calculation (SA302) has been amended to revert to the correct liability initially reported on their 2024/25 Self Assessment tax return.

However, incorrect Class 2 National Insurance letters will continue to be sent out until HMRC have resolved the IT issue in September. Once the problem has been resolved, HMRC will correct the remaining accounts showing a Class 2 National Insurance charge in error. Those affected will be notified when this has been done.

Where a payment has already been made in respect of the incorrect Class 2 National Insurance charge, it will either be refunded or a credit will be added to the taxpayer’s Self Assessment account.

Taxpayers have until 31 January 2026 to submit their 2024/25 Self Assessment tax return. Self-employed taxpayers who have yet to submit their return may wish to wait until this issue is resolved before doing so. Where the return has already been submitted, check the calculation and if it is wrong, make sure HMRC correct it.