A letter from HMRC has landed on your client’s doormat.
It looks official. It mentions deadlines. It uses words like “mandatory”, “digital records”, and “quarterly updates.” Your client has one of two reactions. They panic and call you immediately. Or they put it on the kitchen counter, assume it can wait, and call you in January 2027 when it absolutely cannot.
Either way, it becomes your problem.
This post tells you everything you need to know about the MTD letter, what it means, what your clients are likely to get wrong, and exactly what you need to do about it.
What Is an MTD Letter?
An MTD letter is an official mandation notice from HMRC informing a taxpayer that they are required to join Making Tax Digital for Income Tax (MTD for IT) from 6 April 2026.
HMRC sends these letters to individuals whose gross income from self-employment, property, or both exceeded £50,000 in the 2024-25 tax year. The letter confirms that from April 2026, they must keep digital records and submit quarterly updates of income and expenses through MTD-compatible software.
It is not a request. It is a notice.
And here is the part HMRC buries near the bottom: the letter explicitly tells your client to share it with their accountant or tax adviser. That is your cue.
What Does the MTD Letter Look Like?
Your client will ask if it’s real. Or they won’t ask and will quietly bin it.
Here’s what they’re holding.
It arrives on official HMRC letterhead. HM Revenue & Customs, crown logo, top left. It references their Unique Tax Reference and qualifying income. It tells them their total income was over £50,000 from self-employment and that from 6 April 2028 they will need to use MTD-compatible software to report income and expenses.
Below is the template letter so you know exactly what your clients are holding.
Brief your clients before it arrives. A client who knows what to expect does not call you at 11 pm, convinced they are being defrauded.
Who Is Receiving MTD Letter from HMRC?
HMRC has sent the letters in three batches based on when the taxpayer filed their 2024-25 Self Assessment return.
The first batch went out in November 2025 to taxpayers who filed early, specifically by the end of August 2025. The second batch followed between 2 and 13 February 2026 for those who filed between September and November 2025. The third and final batch is being dispatched between 16 and 27 March 2026 for anyone who filed from December 2025 onwards. Some of those letters will not arrive until early April.
That means right now, today, letters are still landing.
Not every mandated taxpayer will have received one yet. And some will not have opened it. That is not your client’s problem to solve. It is yours.
What Does the MTD Letter Say?
Your clients will forward it to you with a single line: “Do I need to do something about this?”
Here is what the letter tells them.
From 6 April 2026, they must keep digital records of all business and property income and expenses. They must submit quarterly updates to HMRC through MTD-compatible software. They must choose and set up that software before April.
The letter also confirms a soft landing on penalties. No late submission penalties will apply to the first four quarterly updates for 2026 starters. This is welcome news. It is not a reason to delay.
One more thing the letter reminds them: the standard Self Assessment return for 2025-26 must still be filed by 31 January 2027. MTD does not replace it. Both obligations exist.
Does My Client Have to Register If They Got an MTD Letter?
This is the question that matters. And the answer is more nuanced than a yes or no.
Receiving a letter does not automatically mean a taxpayer is mandated. Not receiving one does not mean they are exempt. HMRC is sending letters based on the information they hold, but the legal responsibility to check eligibility and register sits with the taxpayer or their agent. That is you.
Here is where clients will get it wrong.
Some will assume their income has dropped below £50,000 this year, and that lets them off. It does not. Mandation is based on 2024-25 gross income figures, not 2025-26. Even if your client has had a quieter year, if they were over £50,000 last year, they are in scope.
Some will assume the letter is a mistake and ignore it. It might not be a mistake.
Some will assume not getting a letter means they are safe. It does not. If their 2024-25 gross income from self-employment or property exceeded £50,000, they are mandated regardless of whether a letter reached them.
Exemptions do exist for those with a confirmed digital exclusion. HMRC has received around 2,200 exemption requests so far. If your client has one confirmed, they can disregard the letter. Everyone else cannot.
If your client is in scope and has not yet registered, they are already behind.
What Should Accountants Do When a Client Receives an MTD Letter?
Do not wait for the forwarded letter. By the time it lands in your inbox with a question mark, you should already know which of your clients are affected.
Here is your action plan.
The 90% Problem
As of mid-March 2026, 864,000 taxpayers are mandated to join MTD for IT by 6 April 2026.
81,000 have registered.
That means roughly 783,000 people, 90% of everyone who needs to act, have not. Some do not know. Some are waiting. Some are assuming their accountant is handling it. Some are hoping it goes away.
It will not go away.
What this means for your practice is straightforward. A significant wave of last-minute registrations, panicked calls, and rushed software setups is coming. The question is whether you are managing that calmly because you planned for it, or firefighting it because you did not.
The practices that identified their in-scope clients weeks ago are already in control. The ones that have not are about to find out what 90% of unprepared clients looks like in April.
What Else Accountants Need to Know Beyond the MTD Letter
The MTD letter is the immediate problem. It is not the only one.
Final Thoughts
The MTD letter has arrived.
For most of your clients, it is the first time Making Tax Digital has felt real. Not a government consultation. Not an industry headline. A letter with their name on it and a deadline attached.
Your job now is not to wait for them to forward it. It is to already know who is affected, already have a plan, and already be one step ahead of the panic.
6 April 2026 does not move. The only thing that moves is how prepared you are when it gets here.
MTD Resources Worth Bookmarking
Everything you need to get your clients ready, in one place.
- Get ready for MTD: an agent toolkit – Guidance – GOV.UK: GOV.UK’s official guidance for agents handling the transition.
- Top 9 Totally Free MTD Software for Accountants in 2026: No budget for software? Start here.
- Charge Your Worth: Guide to Pricing MTD ITSA Services: A practical guide to charging for the additional work MTD creates.
- MTD ITSA Engagement Letter Template | FigsFlow: Get the paperwork right before April.
Frequently Asked Questions (FAQs)
The MTD letter is an official mandation notice from HMRC informing a taxpayer that they must join Making Tax Digital for Income Tax from 6 April 2026. It is sent to individuals whose gross income from self-employment or property exceeded £50,000 in the 2024-25 tax year.
It means HMRC believes you are required to keep digital records and submit quarterly income and expense updates through MTD-compatible software. It is not a warning. It is a legal requirement. If you are in scope, you must act.
Yes. The letter itself tells you to. HMRC does not send copies to tax agents, so your accountant will not have seen it unless you share it. Forward it as soon as it arrives. The sooner they know, the sooner they can get you set up.
The mandation date is 6 April 2026. That is when digital record-keeping and quarterly reporting must begin. There is a soft landing on penalties for the first four quarterly updates, but the obligation itself starts on that date, regardless of when the letter arrived.
No. HMRC only sends the letter to the taxpayer. Agents receive no copy and no notification. If your client has not forwarded it, you will not know it has arrived. That is why proactively identifying in-scope clients matters more than waiting for the letter to land in your inbox.
