Theresa May’s top adviser Olly Robbins, accused of pushing for a “soft Brexit”, has purged the Brexit department of 50 of its best negotiating staff following the departure of the pro-Brexit minister David Davis.

The career bureaucrat and Soviet Union admirer (pictured, above left) is accused of a “power grab” after Mr Davis (pictured, right) stepped down in protest of the Prime Minister’s plan to keep the UK tied to European Union (EU) trade rules.

According to The Sun, he has moved quickly to strip the Department for Exiting the European Union (DExEU) of its 50 “best negotiating staff”, securing himself more power in Whitehall.

Sources claimed earlier this month that Mrs May and Mr Robbins were moving to sideline or even abolish Mr Davis’s DExEU as it was more pro-Brexit and was pushing plans for a clean Brexit.

The 50 negotiating experts will now move into the Cabinet Office, where they will fall under Mr Robbins’ direct control, further expanding his already extensive power over the Brexit process.

Brexiteers who back a clean exit from the EU have long worried about the Civil Service’s control of Brexit planning, as they suspect them of pushing a “soft Brexit” favoured by the establishment rather than voters.

The new Brexit Secretary, Dominic Raab, has ensured that, unlike his predecessor, he will be copied in on all the advice and demands that Mr Robbins sends Mrs May, amid the concerns about his and the Civil Service’s influence.

Confirming the staff changes, a Whitehall source said: “This is a sensible backroom shift that reflects the surge in negotiating intensity we have been seeking and allows us to achieve the best deal.

“[Mr Raab] will be an insider supporting the PM, privy to all advice and ensuring there is ministerial accountability. There will be no more policies by surprise.”

However, pro-Brexit critics dismissed the promise to keep Mr Raab informed as a minor concession amid a larger win for Mr Robbins and his agenda.

A government insider told The Sun: “Olly has managed to pull off another land grab. It’s a significant weakening of Dom’s new department and another bureaucratic win for Olly. DexEU officials are beyond furious.”