How to Deal With HMRC’s Tax Snoopers & Challenge Mansion Tax

 

FULL GUIDE: How to Deal With HMRC’s Tax Snoopers & Challenge Mansion Tax

From 1 April 2028, the legal owner of any home in England worth £2 million or more at 2026 values pays a yearly charge on top of council tax. The Valuation Office, now part of HMRC, is deciding which homes are in and which band they sit in. Here is a basic timetable:

When	What
Now to autumn 2027	VO builds its list using a computer valuation model checked by a valuer
Autumn 2027	VO publishes a draft list, owners can appeal and correct facts
March 2028	First bills go out
1 April 2028	Charge starts, there is an 8-month window to challenge your band opens
2033	First revaluation, then every 5 years

Guido Fawkes has produced a guide on what to do in this process. Don’t let them get away with it…

Initial Steps

• Consider getting your own counter-valuation. Commission a RICS Red Book valuation – this is important if your home sits within about 10% of £2 million, £2.5 million, £3.5 million, or £5 million.
• Photograph defects including damp, subsidence, a failing roof, or dated interior to lower value. The consultation indicated a run-down home will not be valued as if in good repair…
• Subject Access Request HMRC for what it holds on you, which is free, and they have to reply within a month. Ask for all Valuation Office records linked to your address.
• Strip your home from sites HMRC uses. The taxman has said it will use Rightmove and Zoopla listings, map and aerial images, sales data, and the Land Registry. Rightmove will delete the photos, floorplan, and description from your address record if you send proof of ownership and ID. It does this within seven days. Ask Zoopla and OnTheMarket for the same…
• Ask Google to blur your home on Street View through the “Report a problem” link.
• Ask MHCLG to hide your EPC, which shows floor area, from public search database.

When an inspector comes to your home

• You can refuse entry the first time you are asked with no penalty. Without your consent, a valuation officer has to get approval from the First-tier Tribunal and then give you three working days of written notice before entry.
• Ask for ID, the reason for the visit, and the specific law. The occupier should be told the purpose of the visit and what powers apply by the Home Office code. If the officer has no tribunal approval they are overreaching.
• Refuse a visit then confirm in writing and say: “I do not consent to entry to my home or land. Please put any request in writing.” Follow up by email or letter quickly. The £200 fine is for deliberately obstructing an officer using their powers…
• Delay grounds: Wanting someone with you, having children at home, or feeling unsafe.
• You can withdraw implied consent to walk up to your door with a gate sign or a letter to HMRC saying Valuation Office staff may not enter without tribunal approval. If you want to go the whole hog…

Formal notices

• Only a notice served under section 27 of the 1992 Act puts you under a legal duty to answer the Valuation Office. Ignoring phone calls, regular letters, and online questionnaires carry no penalty.
• If it is a section 27 notice then use 21 days to respond. You only have to give information already in your possession or control. You do not have to measure rooms or commission a floor plan. Failing to reply without a reasonable excuse carries a fine of up to £500…

If HMRC goes to tribunal for entry

• The tribunal may approve entry only if satisfied the officer “needs to value the dwelling”.
• If HMRC tells you it is applying you should write to the tribunal straight away, quote your address, and ask to make written objections and attend hearings.
• Argue that HMRC does not need to come in.
• If entry is approved ask the tribunal to limit it. The law lets the tribunal set the terms of the visit including whether it can run over more than one day. Ask for a single visit at a fixed time with named officers, a list of rooms, no photographs, and the right to have someone with you.
• During the visit, watch and record it all.

Challenge the draft band

• The draft list, due in autumn 2027, is the easiest time to move your valuation. The Valuation Office can fix factual errors at this stage without a formal challenge.
• Look for incorrect valuation evidence.
• Send corrections in writing with evidence. Use all available to drag down value. Send it quickly because VO wants “reasonable time”.
• Demand the evidence behind your band. The government has promised that decisions will come with the evidence and reasoning behind them…

Challenge and appeal

Once the final list is out, you have eight months to challenge your band with the Valuation Office. If it says no, you can appeal to the Valuation Tribunal for England for no cost:

Stage	Your deadline	Govt deadline
Band challenge to the Valuation Office	8 months from the first list and 6 months for later bands or new owners	4 months to decide
Band appeal to the Valuation Tribunal	3 months from the Valuation Office decision	None set
Liability challenge to the council	No time limit	2 months to decide
Liability appeal to the Valuation Tribunal	2 months from the council’s decision, or 4 months from first contact if it never replies	None set
Appeal to the High Court, on a point of law only	4 weeks from the tribunal’s decision	None set

• Team up with neighbours. Share details and try to file at the same time.
• Send your evidence to the Valuation Office four weeks before the hearing. Bring all evidence.
• Go again when you can. A new owner, a band change or another revaluation each opens a new six-month window. Liability challenges can be made at any time…

Other options

• Complain about conduct. The Valuation Office runs a two-tier complaints process aiming to answer each tier within 20 working days. After that you can go to the Adjudicator’s Office.

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