Downing Street has conceded that it cannot say whether any other ministers or their spouses have or have previously held non-dom tax status, or whether Boris Johnson will take any steps to find this out. It came as Keir Starmer called on Boris Johnson to “bring this saga to a close” and say whether any other ministers had taken such efforts to reduce their tax bills. No 10 has confirmed that Christopher Geidt, the independent adviser on ministers’ interests, is to examine the interests and declarations of Rishi Sunak, after the chancellor requested this to happen. Johnson’s deputy spokesperson said that while the inquiry would look into declarations about the non-dom tax status of Sunak’s wife, Akshata Murty, it would not necessarily look at Sunak’s decision to maintain a US green card for a period as an MP and minister. After it emerged that Murty does not pay UK tax on overseas earnings – which she has since agreed to do – the health secretary and former chancellor, Sajid Javid, said he had also held non-dom status for six years while he worked as a banker. Asked if they could confirm that no other ministers or spouses were in the same position, the spokesperson said: “Ministers are required to make the relevant transparency declaration, but it wouldn’t be for me as an individual to know someone’s personal tax arrangements. “The relevant transparency declarations are made. Some of those are made public, but where it can relate to private tax information, sometimes that isn’t made public, for the reason that it is private tax information.” Asked if Johnson would now try to find out whether any ministers had formerly been non-doms – MPs and peers are barred from having the status – or any spouses still had it, the spokesperson said they did not know. In a statement on Monday, Starmer said: “To appoint one chancellor with suspect tax affairs is sloppy, to appoint two is a habit.” The Labour leader added: “Boris Johnson needs to bring this saga to a close and confirm that no other sitting Conservative minister is doing or has done anything to reduce their own personal tax bill, while they preside over the biggest tax hike in 70 years.” Starmer has asked for answers within 24 hours on whether any minister had used non-dom status, benefited from offshore trusts or had other links to tax havens, or used tax minimisation schemes subsequently condemned by HMRC. Speaking at a press conference on Friday, Johnson said he had not known about Murty’s tax status. Asked if the prime minister knew Sunak had held a green card allowing him US residency, the spokesperson said: “I haven’t asked him with regards to the green card. But it’s not a requirement to provide that information to the prime minister.” They added that they did not know if Geidt’s inquiry would look into the green card issue. On Sunday, Sunak wrote to Johnson to formally ask that the prime minister refer his financial arrangements and declarations to Geidt. This had now happened, the spokesperson said: “I’m not aware of whether Lord Geidt himself has begun his work, but I can confirm that the prime minister has agreed to the request from the chancellor for Lord Geidt to undertake this work.” The results would be published “in a timely manner”, they added. Earlier, the environment secretary, George Eustice, said he had never held non-dom status but could not speak for any colleagues. Asked if he knew whether other ministers might come forward, Eustice said on Sky News: “Well I don’t, all I can tell you, as I said, I’m not the accountant for my ministerial colleagues in cabinet, I don’t know anybody who may or may not have had non-dom status. I can tell you that I never have and would never seek to have one.” Eustice said he was confident Sunak had done the right thing. “The man who is chancellor at the moment has paid all of his taxes and paid taxes on his income and declared all of that in the UK and he’s been clear about that,” he said. On Sunday, Angela Rayner, Labour’s deputy leader, wrote to Johnson and Geidt seeking answers on issues including whether Sunak had benefited from the use of tax havens, and whether his status as a green card holder while an MP and minister meant he had been legally a permanent US resident