Angela Rayner has admitted that she underpaid stamp duty on her £800,000 seaside flat, after coming under intense pressure to be more transparent about her property arrangements.

The deputy prime minister has referred herself to the prime minister’s ethics adviser after confirming she will have to pay more of the property tax. She incorrectly paid the lower rate on the apartment in Hove, she said. Experts have said the bill could run to as much as an extra £40,000.

The confirmation that she has underpaid tax could place Rayner’s position in jeopardy as Labour, which is trailing behind Reform UK in the polls, has struggled to convince swathes of the public it is on the side of working people.

The senior Labour figure could also face charges of hypocrisy as the government is expected to increase taxes on property owners in the autumn budget.

In a highly personal statement to the Guardian, Rayner said she “deeply regretted” the error had been made, after classifying the flat as her only property, despite spending much of her time with her children at the family house in Ashton-under-Lyne, Greater Manchester.

Months before the purchase she had put her stake in her constituency home in Ashton into a trust, which was originally set up in 2020 to manage a payment to one of her sons after a “deeply personal and distressing incident” as a premature baby which left him with life-long disabilities.

In May 2025, when she bought the south coast property, she was advised by lawyers over the level of stamp duty required, she said. Subsequently, tax experts had told her that the flat could not be treated as her only residence, because of the provisions of the trust.

Tax experts say even though she gave up her financial stake in the home after her divorce, Rayner would be regarded as still owning it if she or her children were a beneficiary under the trust and entitled to occupy the dwelling for life.

As the flat was an additional dwelling, she would be expected to pay the higher stamp duty rate of £70,000, rather than the £30,000 she actually paid. She is now working with HM Revenue and Customs to establish exactly how much is due.

Regardless of ownership, the Ashton property remains her family home and where she is registered for most official and financial purposes, including council tax and the electoral roll. It is where her children live full-time, while she and her ex-husband take turns living at the house and caring for them.

“While I do not find it easy to publicly discuss personal and sometimes distressing family matters, I have always taken my responsibility as an MP and deputy prime minister seriously and tried to be as open as possible while protecting my family,” Rayner told the Guardian.

“To address the allegations made against me I have now taken the difficult decision to explain why my arrangements are as they are.”

Downing Street had revealed on Monday that Rayner was prevented from publicising all of the details about her property ownership by a court order. In the interests of transparency, she applied to the court and was given permission to discuss them publicly on Tuesday night.

In her statement, Rayner said: “When purchasing the property my understanding, on advice from lawyers, was that my circumstances meant I was liable for the standard rate of stamp duty.

“However, given the recent allegations in the press I have subsequently sought further advice from a leading tax counsel to review that position and to ensure I am fully compliant with all tax provisions.

“I have now been advised that although I did not own any other property at the time of the purchase, the application of complex deeming provisions which relate to my son’s trust gives rise to additional stamp duty liabilities.

“I acknowledge that due to my reliance on advice from lawyers which did not properly take account of these provisions, I did not pay the appropriate stamp duty at the time of the purchase. I am working with expert lawyers and with HMRC to resolve the matter and pay what is due.”

She added: “The arrangements I have set out reflect the reality that family life is rarely straightforward, particularly when dealing with disability, divorce and the complexities of ensuring your children’s long-term security. Every decision I have made has been guided by what I believe to be in my children’s best interests.

“I deeply regret the error that has been made. I am committed to resolving this matter fully and providing the transparency that public service demands. It is for that reason I have today referred myself to the independent adviser on ministerial standards, and will provide him with my fullest cooperation and access to all the information he requires.”