Challenging HMRC 'Discovery' Assessments
20 Aug 2025 • Tax Disputes and Investigations
Written by
HMRC issue Discovery Tax Assessments when it feels that there is additional tax to be recovered and a Compliance Check investigation/enquiry has not been opened in time.
Get specialist tax investigation help today: +44 (0)20 7710 3389
In certain cases, HMRC has the right to issue Discovery Tax Assessments for the previous 20 years. While the Section 29(1) TMA 1970 Discovery powers are broad, they do have limitations. One should always be alive to challenging the validity of a Discovery Tax Assessment by way of an appeal. Clients/advisers should ask themselves a number of questions:
Is there a ‘Discovery’ – is there actually any evidence to support HMRC’s belief that you have under-paid tax or received too many tax reliefs?
Was any return entry in question not in accordance with a generally prevailing practice at the time?
Was the situation brought about carelessly or deliberately?
The Officer could only have reasonably been expected to be aware of the situation on the basis of the information made available to him after the Self-Assessment enquiry window closed and not before it?
Has the Discovery Tax Assessments been made in accordance with the correct time limit for the raising an assessment based on the established behaviour?
If the answer is “No” to any of the above then the Discovery Tax Assessment is not valid.
How can we help?
We have a proven track record in managing Discovery Tax Assessments to minimise a client’s exposure. As part of our service we review any Discovery Tax Assessment and present you with all available options and what the consequences of taking each option will be.
Where appropriate, we will tell you how best to challenge any Discovery Tax Assessment. Should there be any exposure we will protect you from any unnecessary tax, interest and penalty, thus minimising HMRC publishing details about you on its ‘Tax Defaulters’ website. In the most serious of cases, our involvement has prevented our clients from being criminally investigated or, worse still, prosecuted.
Putting it simply, we provide a discreet and comprehensive service that is tailored to meet your unique needs and protect your interests.