Do You Need an Accountant for Self Assessment? UK Guide

You do not legally need an accountant to file Self Assessment. Many people can submit a straightforward return themselves through HMRC or compatible software. Professional help becomes more valuable where income, reliefs, records or tax residence are complex.

When doing it yourself may be reasonable

• one simple sole trade with organised records;
• straightforward employment plus modest self-employment;
• no foreign income, gains or complex reliefs;
• clear allowable expenses and no major asset purchases;
• enough time to learn the process and meet deadlines.

The taxpayer remains responsible for accuracy whether or not an adviser is used.

When an accountant can add value

• multiple businesses or property portfolios;
• foreign income, non-UK residence or domicile issues;
• capital gains, crypto or share schemes;
• partnerships and basis-period adjustments;
• large losses or relief claims;
• pension annual allowance or high-income tax planning;
• VAT, payroll or CIS reconciliations;
• poor or incomplete bookkeeping;
• HMRC enquiries, disclosures or overdue returns;
• MTD for Income Tax implementation.

What an accountant should do

A normal Self Assessment engagement can include:

• reviewing records and identifying missing information;
• preparing accounts or income schedules;
• calculating tax, National Insurance and payments on account;
• considering relevant allowances and reliefs;
• preparing and submitting the return after approval;
• providing payment instructions and filing confirmation;
• answering routine HMRC queries within the agreed scope.

Tax planning, bookkeeping corrections, VAT returns and enquiry work may be separate services.

What an accountant cannot do

An adviser cannot make private costs deductible, guarantee HMRC will not enquire or file accurately without complete information. You must review the return, disclose all income and approve submission.

Regulation and qualifications

“Accountant” is not a universally protected title in the UK. Look for relevant qualifications and membership, such as ICAEW, ACCA, ICAS, CAI, CIOT or ATT, depending on the work. Check the public member directory and disciplinary status.

Anti-money-laundering supervision

A tax or accountancy service provider must normally be supervised for anti-money-laundering purposes. Expect identity, address and source-of-funds checks. Reluctance to perform them is a warning sign.

Questions to ask

1. Who will do and review the work?
2. What qualifications and relevant sector experience do they have?
3. What is included in the fixed or hourly fee?
4. Are bookkeeping corrections, calls and HMRC queries extra?
5. What records and deadlines do they require?
6. Do they hold professional indemnity insurance?
7. How is data secured and returned?
8. What happens if the engagement ends?

Engagement letter

It should define responsibilities, deadlines, fees, limitation of scope, data protection, complaints and termination. Confirm who submits the return and who pays tax. An accountant’s filing software acknowledgement should be supplied.

Can an accountant reduce the tax bill?

A competent adviser can identify legitimate expenses, allowances, elections and timing issues. They should not promise a predetermined refund or encourage false claims. Tax savings depend on facts and law.

Late or messy records

Contact an accountant early. Emergency work near 31 January costs more and may require estimates. Filing on time with permitted provisional figures can sometimes limit penalties, followed by prompt amendment.

Using an agent with HMRC

Authorise the agent through HMRC’s formal process. Do not give them your Government Gateway password or authentication code. Agent authorisation permits defined access but does not transfer liability.

Cost versus benefit

Compare the fee with time saved, risk reduction, quality of records and potential legitimate reliefs. A simple return may not justify extensive advice; a complex return can cost much more if errors are corrected later.

Red flags

• guaranteed refunds or percentage-of-refund fees without explanation;
• no engagement letter;
• requests for your HMRC password;
• unwillingness to show qualifications or AML supervision;
• filing without your approval;
• claims unsupported by records;
• fees hidden until after submission.

Related: doing your own Self Assessment.

Official guidance

• HMRC: appoint a tax agent
• HMRC: choosing a tax adviser

This guide is general information. Choose an adviser competent for the actual complexity.