How will the 'Mansion Tax' impact estate planning?

Inheritance tax is increasingly something more families will need to think about at some stage, particularly where a large share of wealth is tied up in property. The proposed mansion tax could affect estate planning by adding an extra annual charge to high value residential property, which will mean some families will need to rethink their plans for passing on wealth.  

For those with a large proportion of their estate tied up in property, it could make decisions around gifting, succession, liquidity and long term affordability more important, particularly as the rules depend on how homes are valued when the charge begins.

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Added to that the Government is consulting on how the proposals will work in practice. One suggestion is to defer payment until after death for those on lower incomes. Although not set in stone, this could mean an even bigger inheritance tax bill than expected making forward planning crucial.  

What is the mansion tax?

The term ‘mansion tax’ is being used as shorthand for the government’s new High Value Council Tax Surcharge. It applies to owners of residential property in England worth £2 million or more at 2026 prices, and it is separate from the existing Council Tax system. The official charging structure starts at £2,500 a year for homes valued between £2 million and £2.5 million, rising to £7,500 a year for properties worth £5 million or more. The government says fewer than 1% of properties in England are expected to fall within scope.  

From an estate planning point of view, that matters because it adds a recurring cost to retaining a valuable family home. For some households that will be manageable. For others, particularly those who are asset rich but cash poor, it could push property higher up the list of assets that need reviewing as part of a long term plan.

How will property values be calculated?

The surcharge will not be based on the current Council Tax bands, which still rely on property values from 1991. Instead, the Valuation Office Agency will carry out a separate targeted valuation exercise in 2026 to identify which properties are worth £2 million or more and to place them into one of four surcharge bands. The government has also said revaluations will be carried out every five years.  

That distinction is important. A property sitting in a higher Council Tax band today does not automatically fall into the mansion tax regime, and a change to a home’s Council Tax band will not decide whether the surcharge applies. For estate planning, this means families should avoid relying on rough assumptions or old valuations. If a property is anywhere near the threshold, an up to date professional valuation becomes far more useful, especially if future gifting, downsizing, trust planning or a potential sale is already being considered.

When will the mansion tax apply?

The government plans to introduce the surcharge from April 2028. Eligibility will be based on the separate valuation exercise carried out in 2026, with charges then collected from 2028 onwards. The amounts will rise each year in line with CPI inflation from 2029 to 2030 onwards.  

That timing gives affected families a planning window, but not an especially long one. Anyone with property close to or above the threshold has time to review ownership and funding arrangements before the charge starts. In estate planning terms, that may include asking whether the current owner should continue holding the property personally, whether a move is already likely in later life, and whether enough liquid capital exists to cover future annual charges alongside maintenance, care costs and any eventual inheritance tax bill.

Where will the money raised from the mansion tax go?

Although the surcharge will be collected alongside Council Tax by local authorities, the revenue is intended for central government rather than being retained locally in the way Council Tax normally is. The official fact sheet says the measure is expected to raise around £430 million a year from 2028 to 2029 to support funding for local government services, while the Budget and OBR documents put the annual yield at roughly £0.4 billion by the end of the decade.  

For estate planning, the destination of the money is less important than the policy direction behind it. The broader message is that higher value property is being asked to bear more of the tax burden. That may encourage more clients to think of the family home not just as a place to live, but as a taxable asset whose ongoing cost could continue to change over time.

Will people sell property to avoid the mansion tax?

Some will certainly consider it, but many will not rush into a sale on tax grounds alone. The annual charge is meaningful, yet for many owners of homes worth well over £2 million it may still be smaller than the emotional and practical costs of moving. In other cases, particularly for older owners with limited income, the surcharge could become one more reason to downsize earlier, release capital, or rethink whether a large property is the best vehicle for passing wealth down a generation.

That is where estate planning becomes practical rather than theoretical. A home that has risen sharply in value can leave a family with substantial paper wealth but limited cash flow. An extra annual charge, on top of existing running costs, may strengthen the case for simplifying the estate while the owner is still able to make deliberate choices. The government has also said it intends to put a support scheme in place for those who may struggle to pay, although the detailed design of that support is still a matter for consultation.  

Is mansion tax paid in addition to council tax?

Yes. The surcharge is explicitly in addition to existing Council Tax, not a replacement for it. Current Council Tax bands will still apply and will not be used to determine surcharge eligibility.  

This is one of the reasons the measure matters for estate planning. It is an extra annual expense layered on top of the property costs families already face. The government has argued that this corrects an imbalance in the present system, noting that in 2024 to 2025 Council Tax raised £40.3 billion across England and that the average Band D charge for a typical family home was £2,280, which was £250 more than a £10 million property in Mayfair paid under Westminster’s Band H charge.  

Why is the mansion tax being introduced?

The official case is fairness. In Budget 2025, the government said the current system leaves some very expensive homes paying less in annual local property tax than ordinary family homes, because Council Tax is still rooted in 1991 values. The surcharge is therefore being presented as a way to make owners of the highest value residential property contribute more. The Budget also frames it within a wider shift towards taxing wealth and asset based income more heavily.  

That wider context is the real estate planning takeaway. The mansion tax does not, by itself, rewrite succession planning. What it does do is reinforce the need to look at property wealth holistically. Where a large share of an estate sits in a high value home, families may need to pay closer attention to liquidity, future liabilities and whether the property still serves the family’s goals. In that sense, the impact on estate planning is not simply the annual bill. It is the way that bill may prompt earlier and more realistic conversations about how wealth is held, who will inherit it and how sustainable that plan really is.

How we can help

Good estate planning starts with making sure your arrangements still reflect your wishes and your circumstances. That could mean reviewing your will, considering whether trusts may be appropriate, looking at how property and other assets are owned, and checking whether your wider financial plan is set up to pass on as much wealth as possible in a tax efficient way. A free initial conversation with one of our advisers can be a helpful first step towards getting on top of the changes.

There is some speculation that the introduction of a mansion tax could affect the appeal of properties around or above the £2 million threshold. If buyers know a home will come with an extra annual tax charge, that could make some properties less attractive and place downward pressure on values at the margins. That may not happen in every case, and much will depend on how the rules are finally applied, but it is another factor that homeowners may need to keep in mind when thinking about long term estate planning.

With that in mind, financial advice can be especially valuable. Where a large part of your wealth is tied up in property, even a relatively modest policy change can have wider implications for gifting, retirement income, inheritance tax planning and the overall shape of your estate. Taking advice can help you understand how the proposed mansion tax may affect your plans and what options may be available to you for the best financial outcome.

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The Financial Conduct Authority (FCA) does not regulate cash flow planning, tax, estate planning, trusts or wills.

This article is intended for general information only, it does not constitute individual advice and should not be used to inform financial decisions.

The information contained in this article is based on our understanding of legislation, whether proposed or in force, and market practice at the time of writing. Levels, bases and reliefs from taxation may be subject to change.