Around a quarter of staff at Britain's business department are working on the country's exit from the European Union, the department said in response to a Freedom of Information request.
More than three years after Britons voted for Brexit in a 2016 referendum, huge amounts of government time and money are being devoted to the country's preparations to leave the bloc, its most significant policy shift in decades.
Prime Minister Boris Johnson has vowed to deliver Britain's departure on Oct. 31, with or without a deal, and his government has ramped up preparations for a no-deal departure.
If and when Britain's exit happens remains uncertain however, after parliament passed a law which would force Johnson to seek a delay if there is no exit deal in place.
Under the Freedom of Information law, Reuters asked several key government departments, including the finance ministry, interior ministry and revenue and customs ministry, how many of their staff were working on preparations for a no-deal exit.
Most responded either to say the cost of providing such information would be greater than the limit provided for under the law, or that they did not have a breakdown between staff working on different Brexit outcomes.
The Department for Business, Energy and Industrial Strategy however said it had around 1,000 full-time equivalent staff working on a range of Brexit-related matters, roughly a quarter of its 4,065 full-time equivalent staff.
It said these staff were already in place before Johnson took office.
The finance ministry said it is and has been increasing the number of its staff who are working on preparations for a no deal, but did not give a number.
The Department for Transport said around 290 of its 2,731 full time equivalent staff were working on Brexit.
With Brexit dominating the political agenda, some have warned domestic priorities have fallen by the wayside.
The Institute for Government think-tank said earlier this year that the reprioritisation of civil servants onto Brexit work had impacted the government's ability to deliver on flagship policies such as reforming the health service and tackling domestic abuse.
"The situation is not going to improve any time soon: if a Brexit deal is agreed, the civil service will have to continue working at full tilt to negotiate and implement the detail of the future UK-EU relationship," it said.
"If there is no deal, the foreseeable future will be a case of all hands on deck to minimise disruption and mitigate any impacts to the UK's security and economy."