This civil servants' union boss says the PM should consider whether Steve Baker is fit to be a minister

Steve Baker was asked by Tory MP Jacob Rees-Mogg in the House of Commons on Thursday to confirm that he had heard that Treasury officials had "deliberately developed a model to show that all options other than staying in the customs union were bad and that officials intended to use this to influence policy".

The apparent foundation for the claim was later called into question by Centre for European Reform director Charles Grant, the man Rees-Mogg named as the source for his claims.

Grant issued a statement that said he "did not say or imply" that the Treasury "had deliberately developed a model to show that all options outside the customs union were bad with an intention to influence policy".Grant's statement was supported on social media by Duncan Weldon, head of research at the Resolution Group, who said he chaired the meeting, and Antoinette Sandbach, the pro-Remain Tory MP, who said she was also present.