A newspaper story accusing U.K. lawmakers of colluding with European Union officials is a "series of lies" that Prime Minister Boris Johnson and his government must answer for, according to the former attorney general and Conservative politician Dominic Grieve.
The Mail on Sunday newspaper splashed its front-page cover with a story suggesting the government was investigating a plot involving foreign governments and a group of lawmakers in Britain who want to stay in the European Union.
The story claimed, crediting unnamed sources, that a recently drafted law preventing Johnson from pursuing a no-deal Brexit had been drawn up with foreign help. Several MPs (Members of Parliament), including the prime minister, have coined it "the Surrender Act."
Dominic Grieve, a remain-supporting MP who helped draft the law, told CNBC's Steve Sedgwick at the Conservative Party conference Monday that the story was "a piece of classic fake news, based on a series of lies."
He said the act was drafted with the help of the commons clerks and independent lawyers who worked for the public good. He further denied discussing the legal work with any EU official and that a related accusation of overseas funding to draft the bill was again false and "actually quite a serious allegation."
A palpably angry Grieve, who is a member of Johnson's ruling Conservative Party, accused the U.K. government of using taxpayer's money to feed the story direct to compliant journalists at the Mail on Sunday. Grieve has said separately that he received a death threat just hours after being named in the story.
"For a government in a Western democracy like the U.K. to behave in this fashion is quite astonishing," he said before adding: "I will be writing to the Cabinet Secretary to say that, ultimately, he has a responsibility for propriety in this government. What is his explanation for this extraordinary event taking place"
Assuming the legislation preventing a no-deal exit is watertight, Johnson must ask the European Union for a further extension of the current Halloween deadline if he hasn't secured an exit deal by October 19.
The prime minister has previously said he would rather be "dead in a ditch" than ask for more time but, equally, there has been little made public of any progress on a withdrawal deal.
Also attending the Conservative Party conference on Monday was pro-Brexit Conservative lawmaker Iain Duncan Smith. The previous leader of the Conservative Party told CNBC that negotiations between the U.K and the EU are underway, albeit slowly.
"At the moment what they are doing is sorting out with the EU, exactly what the parameters are for any future deal … And then they'll put the proposal on the table. They won't do it yet because they haven't completed that process," said Duncan Smith.
The MP added that getting any deal in place to discuss at the European Summit on October 17 and 18 would require some changes in the stance of EU officials.
"The withdrawal agreement, as it stands, will not pass Parliament. They know that so they need to be flexible," he said.
CNBC has contacted Mail Online and the U.K. government for comment but had received no reply at the time of publication.