Islay Robinson explores the latest Budget speculation, the mansion tax threshold and the wider fiscal pressures facing the Chancellor. With borrowing costs and property taxes in focus, he explains why preparation and financing certainty matter for property buyers.

The Chancellor, John Healey, is facing a difficult choice ahead of the Budget on 28 October. The Institute for Fiscal Studies (IFS) says the government needs to find around £36 billion through tax rises or welfare cuts to address the cost of higher inflation on public services and meet its defence spending commitments. Its warning is clear: a “steady-as-she-goes” Budget is not a realistic option.

For property buyers and borrowers, the important question is what that pressure means for the tax position and financing arrangements they are relying on.

One uncertainty appears to have narrowed. The Financial Times and The Sunday Times have reported that Healey has ruled out lowering the threshold for the planned mansion tax, formally known as the High Value Council Tax Surcharge, from £2 million to £1.5 million. The surcharge is due to take effect in England from April 2028, with annual charges ranging from £2,500 to £7,500 depending on the property's value. A lower threshold would have brought substantially more homes into scope. GOV.UK

That is a meaningful development for owners and buyers of higher-value homes. But I would be careful about interpreting it as a sign that property is being spared from the wider Budget debate.

The Mansion Tax Is Only One Part Of The Picture

Last week, I wrote about the possibility of the mansion tax threshold falling to £1.5 million. That now looks unlikely, based on the latest reporting, although the final position should be judged against the Budget announcement and any accompanying legislation.

The wider fiscal challenge has not gone away.

The IFS has based its latest assessment on inflation averaging 3.1% this year and 3.0% next year, above the official projections made in March. Higher inflation increases the cost of public services and puts pressure on government spending commitments.

The IFS estimates that the Chancellor's fiscal headroom could fall to around £20 billion. Separately, EY's October 2026 fiscal outlook estimates headroom at £11.3 billion, down from £23.6 billion in March. These figures come from different analyses and assumptions, rather than representing a single agreed forecast. The difference matters because it illustrates how uncertain the government's room for manoeuvre remains.

The government has also pledged not to increase the main rates of income tax, VAT or employee National Insurance. Raising the required sum through income tax alone would mean an increase of around three percentage points in the main rate, according to the IFS.

That leaves difficult decisions. The government could look at other taxes, spending reductions or delaying some measures until the 2027 Spending Review. But postponing decisions would leave households, businesses and investors carrying more uncertainty in the meantime.

Property Buyers Should Not Assume The Tax Debate Is Over

I would not treat the decision on the mansion tax threshold as the end of the property tax discussion.

The proposed surcharge is one measure against a much larger fiscal gap. Other possibilities, including changes to the tax treatment of share transfers in property-owning companies and Capital Gains Tax, remain matters for the Budget rather than confirmed policy. The Chartered Institute of Taxation's Budget 2026 analysis outlines some of the tax measures discussed ahead of the announcement, while making clear that much of the discussion is based on media reporting and speculation.

For clients buying through companies, the distinction between purchasing a property directly and acquiring shares in a company that owns it can have important tax implications. Any change to that treatment could affect transaction costs and the structure of a purchase.

I am not a tax adviser, and I would not suggest that anyone change a transaction based on speculation. My concern is how a possible tax change interacts with the financing already being arranged.

A lender assesses a loan against the transaction structure and information available during its application and underwriting process. If you expect a Budget measure to affect ownership, the source of funds, affordability or the timing of a purchase, raise that with your finance specialist early and obtain independent tax advice.

The question is whether the loan still works if the tax position changes between offer and completion.

Borrowing Costs Are Part Of The Same Story

There is another part of the Budget debate that deserves attention: the cost of government borrowing.

The IFS has highlighted the increase in borrowing costs since the conflict in the Middle East began. On 7 October, the UK's 30-year gilt yield reached around 6.04%, its highest level in 28 years, amid wider market concerns about inflation and public finances. Reuters

Government bond yields do not translate directly into mortgage rates, but market expectations influence the pricing of fixed-rate mortgages through swap rates and other funding costs. A Budget that reassures investors could help stabilise expectations; one that raises concerns about the public finances could add further pressure.

The Bank of England's next rate decision is scheduled for 5 November, eight days after the Budget. That does not mean mortgage rates will necessarily move in one direction, but borrowers should recognise that fiscal policy, inflation expectations and monetary policy are connected.

A borrower taking a large loan over a long fixed term has different considerations from someone arranging a smaller loan over a shorter period. The right structure depends on the purpose of the borrowing, the repayment strategy, the assets available and how much flexibility the borrower needs.

This is why I would rather discuss the structure of a loan than pretend anyone can forecast the precise direction of rates.

At Enness, we work with more than 1,000 lenders, and their criteria, pricing and appetite can differ considerably. The most appropriate option depends on the borrower's circumstances and the details of the transaction, not simply on the latest market forecast.

My View

The latest reporting on the mansion tax threshold removes one concern for some higher-value property owners, but it does not remove the uncertainty surrounding the October Budget.

There is still a substantial fiscal gap to address, and the measures ultimately announced could affect different borrowers in different ways. Tax treatment, ownership structures, funding costs and completion dates all matter, particularly for complex or high-value transactions.

My view remains straightforward: do not make a property or financing decision based solely on what the Chancellor might announce. Understand the tax implications with an appropriate adviser, establish how the borrowing is structured and consider whether the transaction remains viable if costs or assumptions change.

The Budget is on 28 October. Until the measures are confirmed, preparation is more useful than prediction.

Risk warning: Your home or property may be repossessed if you do not keep up repayments on your mortgage or any other debt secured on it. Some forms of lending, including most lending to companies, are not regulated by the Financial Conduct Authority.

General information: This article is for general information only and does not constitute personal financial, mortgage or tax advice. Budget measures discussed are subject to confirmation. Lending decisions, rates and terms depend on individual circumstances and lender criteria. Property prices can fall as well as rise. Enness does not provide tax, legal or investment advice. Seek independent professional advice before making financial or property decisions.

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