Allies of Boris Johnson have denounced the move to summons him to court to face allegations that he lied to the public during the 2016 EU referendum when he claimed the UK handed £350m a week to Brussels.

The frontrunner in the Conservative leadership contest may face trial for allegedly “lying and misleading the British public” about the consequences of Brexit.

But an aide said that the crowd-funded private prosecution, brought by campaigner Marcus Ball, was “nothing less than a politically-motivated attempt to reverse Brexit and crush the will of the people”.

And rivals in the race to succeed Theresa May as prime minister voiced concern that the prosecution might have a chilling impact on the democratic debate.

Marcus Ball founded the Brexit Justice campaign (Sandra Vijandi) (Image: Sandra Vijandi)

District judge Margot Coleman today summoned Mr Johnson to attend Westminster Magistrates Court to face three charges of misconduct in public office, which he denies. In a ruling, she said that court will hold a preliminary hearing and the case will then be sent to the crown court for trial.

A member of Mr Johnson’s camp said: “The claimant has openly admitted that his plan is to overturn the referendum via a legal challenge and he clearly intends to try and undermine the one man who can truly deliver Brexit.

“The decision to issue a summons is extraordinary, and flies in the face of hundreds of years of British democratic tradition.”

Jacob Rees-Mogg, who is backing Boris Johnson for Tory leader, said: “It is trying to use the courts to achieve a political end which, I think, is neither right or proper.

“This is involving the courts in something that is not their area.

“We need courts and politicians to respect each other, and it is an abuse of process, and a troubling one. It has been brought by people who are resentful of the referendum result.”

Dominic Raab worried about timing of Boris Johnson's legal case

Leadership candidate Dominic Raab, who joined Mr Johnson in campaigning for Leave during the 2016 referendum, told ITV News: “I do worry a little about the timing of this as a private prosecution, and the sense that the cut and thrust of democratic debate ought to be decided by your viewers, rather than in court.

“And I think that in order to preserve free speech and democratic debate that’s something we should all think carefully and consider.”

Asked if he would be willing to go to court to defend the former foreign secretary’s use of the £350m figure, he said: “I answered all these questions at the time. I think we made the case on the basis of net contribution.

“The gross contribution was £350m a week, and I think this is the stuff of democratic debate. Of course no one has presented me with any legal challenge in relation to what I specifically said during that referendum campaign.”

Another contender for the leadership, Matt Hancock, said: “However people voted in the referendum, we shouldn’t have courts judging on political debates. Let’s have robust debate to test arguments – and keep courts out of politics.”