Skip to main content

CYBER SECURITY SOLUTIONS, PROTECT YOUR BUSINESS TODAY

Click here to find out more

Services

Discovery Assessment

Discovery Assessments (s29 TMA 1970)

Discovery Assessments under s29 Taxes Management Act 1970 (TMA 1970) are a further way that HMRC can challenge a tax return.

It should be noted, however, that HMRC should not issue a Discovery Notice simply because they are out of time to enquire into an individual’s tax return under s9A TMA 1970.

There are certain conditions which must be satisfied and various deadlines which must be adhered to.  It is therefore important to understand that there are limits to their use and HMRC can occasionally raise discovery assessments when they are not entitled to do so.

Generally the time limits available to HMRC to open a discovery assessment are as follows:

  • 4 years after the end of the tax year for insufficient disclosure on a return;
  • 6 years after the end of the tax year for loss of tax brought about by carelessness; or
  • 20 years after the end of the tax year if the loss of tax arose by a deliberate error.

Our team has dealt with many discovery notices and where necessary has challenged successfully the validity of the notice.  We can help you to manage the enquiry to ensure the very best outcome.  If you have received a discovery assessment, please call one of the team to discuss how we can help.

Contact us

Contact our Specialist Tax team

Contact the team

Get in touch

Get in touch to speak to one of our specialist advisers and explore how we can help you.

Contact us

Find your local office

Visit your local office. To find your nearest office just enter your town or city below.

Find an office

Latest news

Key VAT considerations for charities and not-for-profit organisations

by Armstrong Watson - 8th September 2026

Modern office boardroom meeting with professionals gathered around a conference table and presentation easel.

What is an Alternative Business Structure (ABS) and how to set one up

by Andy Poole - 8th September 2026

Digital security padlocks connected across a glowing network, representing cybersecurity, data protection and secure online systems.

If you were locked out of your systems tomorrow, what would happen to payroll?

by Rebecca Wilson - 8th September 2026

Digital tax with fingers typing on a laptop

HMRC to begin signing up taxpayers for Making Tax Digital

by Helen Robinson - 7th September 2026

Investment market update

Our Latest Investment Market Update – The Bond Market's Warning Signal

by Justin Rourke & Richard Cole - 7th September 2026