Labour leader Sir Keir Starmer has written to the head of the civil service with a request to start preparations for a potential change of government after the general election.
The letter to Cabinet Secretary Simon Case, sent on Wednesday, comes after Prime Minister Rishi Sunak last week authorised for the talks between Labour and the civil service to commence.
The meetings will be an opportunity for Labour to discuss its agenda for government and establish relationships with potential future colleagues in Whitehall.
A Labour Party spokeswoman said: “Keir Starmer has today written to the Cabinet Secretary to begin the access talks process.”
The process, which will be overseen by Mr Case, is expected to begin before the end of January, PA news agency understands.
Labour is comfortably ahead in opinion polls, with a survey by Savanta published on Tuesday putting Sir Keir’s outfit 17 points ahead of Mr Sunak’s Conservatives.
Another major opinion poll published this week, using a research method that looks to predict constituency-by-constituency results, signalled doom for the Prime Minister, with the Tories said to be on course for a 1997-style wipeout.
The YouGov survey of 14,000 people indicated that the Conservatives could hold on to as few as 169 seats, with Sir Keir entering Downing Street with 385 Labour seats.
Access talks are held in the run-up to a general election, and are the only chance for the Opposition and the civil service to exchange information ahead of a potential handover date after the election.
The Leader of the Opposition must write to the Prime Minister requesting the meetings in order to initiate the process.
By convention, the Prime Minister is expected to respond by authorising the talks ahead of an election.
Reports had suggested that Mr Sunak had delayed agreeing to the meetings but the Cabinet Office last week confirmed he had given the go-ahead.
In a statement issued on Thursday, a Cabinet Office spokesman said: “In line with the long-standing process set out in the cabinet manual, the Prime Minister has authorised access talks between the official opposition and civil service.
“The Cabinet Secretary will oversee and arrange these discussions.”
The Prime Minister has said it is his “working assumption” that he will send the nation to the polls to elect a new Westminster government in the second half of 2024, with October or November thought to be most likely.