The party’s deputy leader, Angela Rayner, has written to the cabinet secretary, Simon Case, asking him to confirm no records related to the Partygate investigation, including electronic messages, have been destroyed.
Her letter, seen by The Independent, also asks Mr Case to confirm if any request to remove evidence has been made by senior officials or special advisers of junior officials.
It follows a report in The Independent in which two sources claimed a senior member of staff told them to “clean up” their phones of anything that could “look like a party” after early reports of gatherings while Covid restrictions were in place in December last year.
The alleged verbal guidance, which a Downing Street spokesperson said they did “not recognise”, is at odds with a written request to staff to keep any records pertinent to the internal investigation being conducted by senior official Sue Gray.
Ms Rayner said: “Aside from the illegality of messages being deleted, there is a real question of fairness and leadership. Senior figures with power over junior officials could be seen to be bullying them into taking action to protect their own skin.”
She added: “It is deeply worrying that staff were reportedly pressured to do something wrong in order to cover up decisions by those at the top.”
On Friday, The Times reported that Ms Gray’s investigation had been “blindsided” by reports of parties at Downing Street the day before Prince Philip’s funeral. The investigating official is said to be concerned that Downing Street staff are withholding information about parties from the probe.
Labour’s deputy leader also asked Mr Case whether he will ensure that disciplinary process will be applied fairly and appropriately to “all those involved” including himself.
Mr Case, as head of the civil service, has the final say on any decision regarding disciplinary action involving officials. Unless other arrangements are made, he will determine what steps to take following Ms Gray’s report, unless they involve ministers or political appointees, in which case that will fall to the prime minister, Boris Johnson.
Labour’s intervention also comes after a warning from the Information Commissioner’s Office in response to the report.
“Erasing, destroying or concealing information within scope of a Freedom of Information request, with the intention of preventing its disclosure is a criminal offence under section 77 of the Freedom of Information Act,” an ICO spokesperson said.
Ms Rayner has formally asked Mr Case to confirm whether the Cabinet Office and Downing Street have referred themselves to the ICO.
She added: “The British Civil Service is known around the world for upholding the highest standards and, as you are of course aware, the Civil Service Code is designed to ensure that officials can conduct their work without fear or favour.
“I am concerned that in order to move on from this raft of scandals that junior staff may lose their jobs in order to protect politicians or their appointees.”
The intervention also follows reports of a plan to save the Johnson premiership which includes officials losing their roles as part of a fightback.
Sources told The Independent Boris Johnson and others in Downing Street had taken to using the informal name “Operation Save Big Dog” for the plan to save the PM.
A spokesperson for Number 10 said they “absolutely do not recognise” the phrase.