More than £100 million of Whitehall contracts have been awarded for Brexit-related professional services since the referendum, new research shows.

Analysis firm Tussell said 85 contracts, including for consultancy, IT, research and legal services have been granted since June 23 2016.

The report, compiled for the BBC, showed contracts awarded by the Cabinet Office accounted for nearly three-quarters of the total (£77.4 million), while the Department for Environment, Food and Rural Affairs had offered the most contracts with 19.

The highest value Brexit-related contracts were for consultancy services – with 28 contracts issued worth £91.7 million – while spending on IT contracts was worth £10.2 million.

Gus Tugendhat, the founder of Tussell, told the BBC: “Even in the best of circumstances, the civil service alone would never have had sufficient capacity to pull off a project like Brexit in the time available.

“Due to the sheer breadth of issues the Government is having to grapple with, it was pragmatic to engage the expertise of consultants – even if it is has led to extra cost for the public sector and a windfall for consulting firms.”

Contracts for Brexit-related research accounted for just over £4 million of the spend, with the report noting “many smaller bodies are worried about the impacts of Brexit, including Visit Britain, the BFI, and local councils across the country”.

A Government spokesman said: “It is standard for Government departments to draw on the advice of external specialists.

“The whole of government is preparing for the UK to make an orderly and successful exit from the European Union, and we are equipping ourselves with the right people and the right skills across government to make this happen.”

Alexander Britton is a reporter with the Press Association.