Boris Johnson faces questions over Dominic Cummings' time in Russia after whistleblower raises 'serious concerns'

Shadow foreign secretary Emily Thornberry writes to counterpart Dominic Raab to raise concerns

Labour has demanded Boris Johnson’s most senior adviser, Dominic Cummings, answers a series of questions relating to his past in Russia after a whistleblower allegedly came forward with “serious concerns”.

In a letter to Dominic Raab, Emily Thornberry queried whether the former Vote Leave director has been granted access to some of the government’s most sensitive “top secret” files.

The shadow foreign secretary said an “official-level whistleblower” had raised “serious concerns” with members of Jeremy Corbyn’s front bench regarding Mr Cummings’ time in Russia in the 1990s after graduating from university.

Copying in the civil service chief Sir Mark Sedwill, and members of Britain’s security services to the correspondence, Ms Thornberry said Labour did not “know the veracity of their claims” but felt compelled to inform them.

In her letter, first published by The Sunday Times, Ms Thornberry asks what level of security vetting Mr Cummings was “subjected to prior to his current appointment” as senior adviser at No 10.

Ms Thornberry then goes on to ask whether those who vetted his security clearance posed questions “about his relationships with academics at Oxford University, and whether any of them ever discussed with him the possibility of working to support the post-Communist Russian government”.

She adds: “Was Mr Cummings questioned about the purpose of, and his activities during, his three-year period of work in post-Communist Russia between 1994-7, including all relationships he established with figures in the fields of Russian politics, intelligence and security.”

Ms Thornberry continues: “I am sure you and the others copied into this letter appreciate the seriousness of these issues, and the reason I feel duty-bound to put to you the concerns raised with the Labour front bench by a whistleblower whose motives we have no cause to question.

“I would therefore be grateful for a response at the earliest opportunity, or if it would be more appropriate to discuss these matters in person with officials on Privy Council grounds, as per previous discussions on security and intelligence matters, I would be happy to do so.”

The Cabinet Office said in response its “does not comment on individuals’ security clearance”. The Independent has also approached Downing Street for comment.