Mr Rees-Mogg first raised the claims in the Commons yesterday when he asked Brexit minister Steve Baker to confirm if he had heard from Charles Grant, of the Centre for European Reform thinktank, that Treasury officials had deliberately developed a model to show “all options other than staying in the customs union were bad”.
Mr Baker initially said the claim was “essentially correct” and “extraordinary”.
But Mr Grant strongly denied the claim and the minister later backtracked after a recording of Mr Grant’s comments was published.
Jacob Rees-Mogg has refused to budge on the issue and today pointed to the recording as further evidence, branding the alleged plot “#TreasuryGate”.
Jacob Rees-Mogg hit out at the Treasury
In the recording, Mr Grant said: “The Treasury is determined to stay in the customs union.
“In private Treasury officials say that they know we are going to stay in during the transition and they hope that when we are in the transition people will understand that the costs of leaving are rather high.
“There is unpublished papers sitting in the Treasury showing that the economic costs of leaving the single market and customs union are much greater than the benefits of free trade agreements with every other country in the world.”
And Mr Rees-Mogg said today those words showed there was a plot to keep Britain in the Customs Union and ministers “must take responsibility”.
He said: “The recording of Charles Grant’s Prospect lunch raises more questions about the Treasury’s behaviour.
“When Mr Grant says ‘The Treasury is determined to keep us in the customs union’ does he mean the Chancellor or officials?
“If the Chancellor, it is a breach of collective responsibility, if officials, against their duty to implement Government policy.
“When Mr Grant refers to ‘unpublished papers’ on the customs union, who commissioned these and authorised him to be told?
The row erupted in the Commons
“Again, if officials, improper for them to tell a partisan think-tank leader before most of the Government or Parliament.
“Mr Grant refers to private conversations with Treasury officials.
“Have these been authorised by Ministers or are officials freelancing?
5/5 The conclusion must be either the Chancellor or his officials are deliberately trying to frustrate Brexit. Ultimately, Ministers must take responsibility #TreasuryGate
— Jacob Rees-Mogg (@Jacob_Rees_Mogg) February 2, 2018
“The conclusion must be either the Chancellor or his officials are deliberately trying to frustrate Brexit.
“Ultimately, Ministers must take responsibility.”
Remaining in the customs union means that Britain would not be allowed to have its own trade policy and would be dictated to from rules drawn up by Eurocrats in Brussels.
Mr Baker has faced calls to be sacked over his initial claim in the Commons and was forced to apologise.
Philip Hammond is under fire
He told the Commons yesterday: “In the context of that audio, I accept I should have corrected or dismissed the premise of my honourable friend’s question.
“I have apologised to Mr Charles Grant, who is an honest and trustworthy man.
“As I’ve put on record many times, I have the highest regard for our hard-working civil servants.
“I’m grateful for this early opportunity to correct the record and I apologise to the House.”
Questioned on the row during her visit to China, Mrs May insisted that civil servants and ministers were “working together” to deliver the best possible Brexit.
Jacob Rees-Mogg doubled down on his claims
Asked by Channel 5 News whether she would sack Mr Baker, the Prime Minister replied: “No. The ministerial code says that the minister should take the earliest opportunity to amend the record that he has given to Parliament and apologise to Parliament. He will do that.”
Downing Street had initially said there was no reason to question Mr Baker’s version of events, before adding he had made a “genuine mistake” after the tape was released by Prospect magazine.
Mr Baker’s initial claims had provoked a furious backlash from the union representing senior civil servants, which accused him of being irresponsible and “cowardly” for failing to challenge the “conspiracy theory”.
The controversy comes hot on the heels of Mr Baker drawing fire earlier in the week for dismissing Whitehall forecasts as “always wrong”.
In his own statement, Mr Grant said he had neither “said or implied the Treasury had deliberately developed a model to show that all non-customs union options were bad, with the intention to influence policy.
“I recall saying to Steve Baker at a Prospect lunch at the Conservative Party conference that I was aware of research that the Treasury had done.
“This apparently showed that the economic benefits of the UK forging FTAs with third countries outside the EU were significantly less than the economic costs of leaving the customs union.”