Angela Rayner is facing fresh scrutiny amid reports she used £160,000 from a trust set up to care for her disabled son to buy a second home on the seafront in Hove.
The Deputy Prime Minister sold a 25% share of her home in Ashton-under-Lyne constituency to the trust for £162,500, according to the Telegraph.
Ms Rayner said on Wednesday that her son Charlie had been born prematurely and received a payout in 2020. The paper said it followed an 11-year legal battle between the Rayner and the hospital where her son was born in 2008.
Ms Rayner has been left fighting for her political future after admitting she did not pay enough tax when buying her seaside flat following days of scrutiny.
She has referred herself to both the Government's independent ethics adviser and to HM Revenue and Customs (HMRC) after making the admission.
Tory leader Kemi Badenoch and Reform's Nigel Farage have led calls for the Deputy Prime Minister to resign.
The Conservatives have called for the taxman to go further and investigate whether Ms Rayner has evaded tax, which would be illegal.
But Sir Keir Starmer is "determined" to save his deputy, according to the Times.
"He wants to do everything he can," an ally of the Prime Minister told the newspaper.
At Prime Minister's Questions on Wednesday, Sir Keir gave his backing to Ms Rayner, telling MPs he was "very proud to sit alongside" her.
Science Secretary Peter Kyle meanwhile told LBC that the Deputy Prime Minister was "being treated very differently" because she was from a working class background.
Ms Rayner referred herself to the Prime Minister's independent ethics adviser Sir Laurie Magnus after admitting she underpaid stamp duty, something the PM described as "the right thing to do".
She has also said she is "working with expert lawyers and with HMRC to resolve the matter and pay what is due".
The Deputy Prime Minister, who is also the Housing Secretary, said she had received inaccurate legal advice that led her to underpay tax when buying a flat in Hove in May.
She has been under pressure after media reports claimed she saved £40,000 in stamp duty on the property because she removed her name from the deeds of a family home in her Ashton-under-Lyne constituency, classifying the Hove flat as her only property despite still spending time at the family house.
The Deputy Prime Minister revealed she considered resigning over the issue after conceding she had made a “mistake”.
Ms Rayner said in a statement on Wednesday she had taken legal advice when she bought the south coast flat, which suggested she was "liable to pay standard stamp duty", but had then sought "further advice from a leading tax counsel" after headlines about the arrangement.
She learned that the initial advice had been inaccurate and she was liable to pay additional stamp duty.
That is because she had put her stake in her constituency home in Ashton into a trust set up in 2020 for her disabled son.
On Wednesday, Ms Rayner explained when she and her now ex-husband divorced in 2023, some of their interest in their home in her constituency was transferred to that trust.
Ms Rayner has said she transferred her share of the house to her teenage son to ensure he had “stability in the family home”.
Tax experts said the Hove property could not be treated as her only residence because of the nature of the trust.
Conservative Party chairman Kevin Hollinrake said her explanation "cannot withstand scrutiny", as he wrote to HMRC calling for a tax evasion investigation.
Mr Hollinrake also called on the tax authority to "consider the application of a penalty for tax evasion", which could be as much as the full £40,000 Ms Rayner is said to have saved.
