Emails sent by Rachel Reeves's husband will be published later today amid an ongoing row over her rented family home.
It comes after the Chancellor admitted last night to the "inadvertent mistake" of failing to obtain a licence to rent out her Dulwich property. She put the south London home - owned with her husband - on the market after moving into No11 Downing Street following Labour's election victory last summer.
A No 10 spokesman said this afternoon: "Following a review of emails sent and received by the Chancellor's husband, new information has come to light. This information has been passed to the Prime Minister and his independent adviser."
But Downing Street stressed the Prime Minister still retains confidence in his Chancellor and guaranteed Ms Reeves will deliver the Budget on November 26. It came after Mr Starmer threw his weight behind Ms Reeves on Wednesday evening following her apology for renting out her family home without a licence.
The Chancellor had told the PM that "regrettably" she and her family were not aware a "selective licence" was needed in their area of Southwark in London, where they rented out their home for £3,200 a month after moving into No 11.
Southwark Council requires people renting out their properties in certain areas to get a licence in advance.
Ms Reeves added: "Regrettably, we were not aware that a licence was necessary, and so we did not obtain the licence before letting the property out. This was an inadvertent mistake. As soon as it was brought to my attention, we took immediate action and have applied for the licence. I sincerely apologise for this error and I would be happy to answer any questions you may have."
In his response, Mr Starmer had said he was happy the "matter can be drawn to a close" after consulting his ethics adviser. He said: "I have this evening consulted with my Independent Adviser on Ministerial Standards.
"He has advised me that in relation to your inadvertent failure to secure the appropriate licence for your rental property - and in light of your prompt action to rectify the position, including your apology - further investigation is not necessary."
The PM added: "It is regrettable that the appropriate licence was not sought sooner and it is right that you have taken the appropriate steps today to address this. It is clear to me that you are treating this matter with the urgency and seriousness it deserves."
Local councils have powers to force people renting out their homes in certain areas to obtain a selective licence. It is designed to protect tenants against landlords letting out poorly-maintained properties, but it also might be introduced because of concerns about persistent anti-social behaviour problems in rental homes.