Brexit: Jacob Rees-Mogg claims civil servants are 'fiddling figures' on EU withdrawal, reigniting conspiracy theory row

Senior Brexiteer Jacob Rees-Mogg has accused Treasury civil servants of “fiddling the figures” on Britain’s withdrawal from the European Union, dramatically reigniting a row over allegations that officials are trying to undermine Brexit.

The chair of the pro-Brexit European Research Group suggested Treasury staff had produced “politically influenced” analysis and repeated his claim that officials are trying to sway policy to keep the UK in the EU customs union.

His comments came a day after his Eurosceptic ally, Brexit minister Steve Baker, was forced to apologise to the House of Commons for initially refusing to dismiss the allegation.

The fresh claims are likely to place more pressure on Theresa May to take action against Tory MPs openly questioning the integrity of civil servants.

Mr Rees-Mogg told the BBC Today programme: “With all forecasts, the assumptions you make at the beginning determine the outcomes that you get.

“If you look at the forecasts the Treasury made before the referendum, they were a humiliation. They were clearly politically influenced.

He added: “The Office [for] Budget Responsibility was set up by George Osborne because the Treasury forecasts had been politicised. It was thought that they were unreliable on political grounds.

“With the referendum and with the EU, the Treasury has gone back to making forecasts. It was politically advantageous for them in the past. It is the same for them now.

“So yes, I do think they are fiddling the figures.”

The explosive claims prolong the furious row that began on Thursday, when Mr Rees-Mogg asked Mr Baker in the Commons chamber whether he had heard an allegation that Treasury officials had “deliberately developed” an analysis designed to “influence policy” in favour of staying in the customs union.

He said the allegation had come from Charles Grant, head of the influential Centre for European Reform think tank.

Mr Baker said he was familiar with the suggestion and called it an “extraordinary allegation”.

However, Mr Grant immediately denied making the claim, and an audio recording of the event in question later confirmed his account.

After an angry backlash and calls for him to be sacked, Mr Baker admitted he had misinterpreted Mr Grant’s comment and apologised to him and the House of Commons.

However, Mr Rees-Mogg refused to back down and insisted his claims were correct.

“The only thing I’ll apologise for is that it’s turned out to be much more serious than I thought,” he said.

He accused the Treasury of “running policy that is not government policy and then giving private briefings to people about it”, saying: “It is not for officials to invent policy.”

“Under the ministerial code, officials are not allowed to brief journalists without specific ministerial permission, so we need to know what is going on in the Treasury.”

Mr Grant “is getting private briefings from the Treasury against government policy”, he added.

Speaking on the same programme, Mr Grant hit back and demanded that Mr Rees-Mogg apologise.

“Mr Baker, a very honourable man, has apologised to me and to the House of Commons for saying things that weren’t quite right. I am surprised that Mr Rees-Mogg hasn’t apologised.”

“The Treasury cares about economics so it is naturally pushing for the sorts of Brexit that minimise the economic damage.”

Responding to Mr Rees-Mogg, a Treasury spokesperson said: “Both Treasury ministers and officials are working hard to deliver the best Brexit deal for Britain. The Prime Minister and the Chancellor have said repeatedly that we will be leaving both the single market and the customs union. Any suggestion to the contrary is simply false”.