Can I ask HMRC for more time to respond?

You can ask HMRC for more time, and doing so is common and generally reasonable, particularly where records are complex, held by a third party, or where you need to instruct an accountant to review the position properly. HMRC caseworkers deal with extension requests regularly and are usually willing to grant a short, sensible extension.

The key is to ask before the deadline passes, not after. A request made in advance, with a clear reason, is treated very differently from silence followed by a late explanation once the deadline has already gone.

There's no statutory right to an extension, so it remains at the caseworker's discretion, but a well-reasoned request with a specific new date is rarely refused outright.

Contact the person named on the letter, using the phone number or address given, and explain specifically why more time is needed. Vague requests, such as "I need more time," are less persuasive than a concrete explanation, for example that records are held by a former bookkeeper, or that an accountant needs time to review a complex set of accounts.

Propose a specific new date rather than leaving it open-ended. This makes it easier for HMRC to agree quickly, and gives you a clear new deadline to work towards.

Always follow up any verbal agreement with a written confirmation, whether by email or letter, so there's no ambiguity later about what was agreed.

If HMRC declines an extension, or if a formal Schedule 36 information notice deadline has already passed, submit whatever you can by the stated date and explain in writing what's still outstanding and why. This shows good faith and reduces the risk of a penalty for non-compliance, even if it doesn't remove it entirely.

For a formal information notice, there is a process to appeal aspects of the notice itself, but that's different from simply asking for more time; check which route is relevant to your specific situation.

Repeated extension requests, or requests made only after a deadline has passed, are less likely to be viewed favourably, so it's worth being realistic about the time you actually need the first time you ask.

Directors often need extra time because company records sit with a bookkeeper, accountant, or payroll provider, and gathering everything takes coordination. Flagging this early, rather than scrambling close to the deadline, keeps the relationship with HMRC constructive.

If your accountant is handling the response on your behalf, make sure they have the letter and any deadline as soon as it arrives, so they have the maximum possible time to prepare a proper reply.

Asking for a reasonable extension costs nothing and can prevent a rushed, error-prone response. Missing a deadline without any communication, by contrast, can lead to penalties and a more adversarial ongoing relationship with the caseworker.

Growth plan clients get tax investigation insurance as standard, covering professional time spent managing deadlines and responses during a compliance check. See /fees.

Don't wait until the deadline has passed to ask for more time.

Don't make an open-ended request; suggest a specific new date.

Don't rely on a verbal agreement alone; get any extension confirmed in writing.