What is the Mansion Tax? When Does it Apply?

If you’ve been following the news, you’ve probably come across the term “mansion tax”. It’s a phrase that’s been widely used since the Government announced plans for a new annual charge on high-value homes, but what does it actually mean for homeowners?

Officially known as the High Value Council Tax Surcharge, the proposed charge is expected to apply to residential properties in England worth more than £2 million. While it isn’t due to come into effect until April 2028, the way properties are valued could have implications much sooner.

Whether you’re buying, selling or simply planning for the future, understanding how the proposed changes could affect you is an important first step. In this guide, we explain how the surcharge is expected to work and what you should be thinking about ahead of its introduction.

What is the Mansion Tax?

Although it’s commonly referred to as the “mansion tax”, its official name is the High Value Council Tax Surcharge.

The proposed surcharge was announced by the Chancellor the Exchequer in the Budget on 26 November 2025 and is expected to be collected alongside council tax from April 2028.

The Government says the aim is to make England’s council tax system fairer. At the moment, some of the country’s most expensive homes pay relatively little council tax compared with properties worth considerably less. The new surcharge is intended to help address that imbalance.

Rather than applying the same charge to every property, the surcharge is based on its value. Under the current proposals, annual charges would start at £2,500 for homes worth between £2 million and £2.5 million, rising through a series of value bands to a maximum annual charge of £7,500 for properties valued at more than £5 million.

Unlike standard council tax, the additional money raised will go directly to the Treasury rather than local authorities.

The Office for Budget Responsibility estimates that around 165,000 households will be affected, representing fewer than 1% of homes in England. The surcharge is expected to raise around £400 million a year by 2029/30.

How Will My Property Be Valued?

Before the surcharge can be introduced, every property needs to be assessed to determine whether it exceeds the £2 million threshold.

The Valuation Office Agency (VOA) is expected to carry out the initial valuations using April 2026 market values, with further revaluations taking place every five years.

For most homeowners, the valuation process won’t involve anyone visiting the property. Instead, the VOA is expected to use information such as recent sales data, planning records, aerial imagery and other publicly available information to estimate a property’s value.

However, valuing high-value homes isn’t always straightforward. Luxury properties are often unique, which means there may be very few comparable sales to rely on. In those cases, a physical inspection may be needed to reach a more accurate valuation.

If you think your property has been placed in the wrong valuation band, you’ll be able to challenge the assessment. While the details of the appeals process are still being finalised, many experts expect there to be a significant number of appeals once valuations are issued.

Why it pays to plan ahead

Although the surcharge isn’t expected to be introduced until 2028, the proposed valuation date of April 2026 means it’s worth thinking ahead.

If your property could be close to the £2 million threshold, taking advice now may help you understand where you stand before valuations are carried out.

A solicitor can explain how the proposed surcharge could affect your property, your estate planning and any future sale or purchase. If necessary, they can also recommend obtaining an independent valuation and support you through any future challenge to the VOA’s assessment.

How Does the Mansion Tax Affect Buyers?

If you’re buying a property worth more than £2 million, the proposed surcharge is another cost you’ll need to factor into your decision.

Unlike Stamp Duty Land Tax, this isn’t a one-off payment. Once you’ve completed your purchase, you’ll become responsible for paying the annual surcharge alongside your council tax.

It’s also worth considering how the new charge could influence asking prices. Homes sitting just above one of the valuation thresholds may become the subject of tougher negotiations, as buyers weigh up the ongoing annual cost of ownership.

For example, a property valued at £2.6 million would fall into a higher surcharge band than one valued at £2.49 million. Although the difference in value is relatively small, the ongoing annual charge could still influence what a buyer is prepared to offer.

If you’re buying a second home worth more than £2 million, it’s important to remember that the surcharge could apply alongside any second home council tax premiums, increasing your annual property costs.

How Does the Mansion Tax Affect Sellers?

If you’re selling a high-value property, it’s worth considering how buyers may respond once the surcharge comes into force.

An additional annual charge is likely to become another point of discussion during negotiations, particularly for properties sitting close to one of the valuation thresholds. While location, condition and market demand will always have the biggest influence on price, ongoing ownership costs could become another factor buyers take into account.

Some homeowners may consider downsizing to avoid paying the surcharge. However, it’s important to look at the bigger picture. Selling one property and buying another can involve significant Stamp Duty Land Tax, legal fees and moving costs, so the annual surcharge is only one part of the financial decision.

What Does the Mansion Tax Mean for Estate Planning?

The proposed surcharge isn’t only relevant if you’re buying or selling a property.

If your estate includes a home worth more than £2 million, it’s a sensible time to review your wider estate planning arrangements. Although the surcharge is separate from inheritance tax, understanding how valuable property fits into your overall estate can help you make informed decisions about the future.

Reviewing your will, considering how your assets are structured and seeking legal advice early can all help ensure your plans continue to reflect your wishes as the rules develop.

How Can Eatons Solicitors Help?

Although the proposed mansion tax is still subject to consultation and some of the finer details are yet to be confirmed, there are practical steps you can take now to prepare.

At Eatons Solicitors, our conveyancing team can help you understand how the proposed changes may affect your individual circumstances.

If you’re buying or selling a high-value property, we’ll explain how the surcharge fits into the wider transaction, highlight any legal or practical considerations and ensure you understand the costs involved before you move forward.

If you’re reviewing your will or planning your estate, we can advise on how the proposed surcharge fits into your wider plans and help you make informed decisions for the future.

For executors administering estates that include valuable property, our probate team can provide clear advice throughout the administration process and identify any issues that need to be considered.

If you believe your property has been placed in the wrong valuation band once assessments begin, we can also work alongside an independent valuation surveyor to support any appeal.

Every property owner has different priorities, and there’s no one-size-fits-all approach when it comes to planning ahead.

Whether you’re buying, selling or simply looking to understand how the High Value Council Tax Surcharge could affect you, our experienced team is here to help. We’ll explain your options in plain English, answer your questions and provide practical advice that’s tailored to your circumstances.