TORY leader hopeful Mark Harper said he could not promise the UK would leave the European Union on October 31, because it “just isn’t possible”.

Formally launching his bid for the Conservative Party top job yesterday, the Swindon-born Forest of Dean MP refused to guarantee Brexit could be delivered by the end of October.

Mr Harper, 49, the former chief whip, would not rule out a no-deal Brexit if the alternative was not leaving at all but "one thing I'm not promising, as much as I'd like, is that we will leave deal or no deal come October 31" because "it just isn't possible".

He claimed to have a "credible, deliverable plan" to get the UK out of the European Union, based on "going back to Brussels to open real and transparent discussions to change the backstop".

Mr Harper, who has not served in office under Theresa May, said that proper, functioning government "can only be enforced by someone who hasn't been party to what has been called the 'worst example of ill-discipline in Cabinet in British political history'".

The self-described "underdog" in the contest said he would go back to Brussels to re-negotiate the Northern Ireland backstop.

While he said he would not take no-deal off the table, Mr Harper warned the parliamentary arithmetic meant no new leader could promise to take the UK out by the latest EU deadline. "One thing I'm not promising, as much as I'd like, is that we will leave deal or no-deal come October 31. Why? It's because I'm being straight with you and it just isn't possible," he said.

"As a chief whip who has had to operate when the numbers were tight, I know how Parliament works and I know how to count."

Mr Harper was raised in Swindon, attended Headlands School and Swindon College, before leaving to read Politics, Philosophy and Economics at the University of Oxford. He returned to his hometown after university, training as an accountant with KPMG, then leaving to work at Intel. He has served as Forest of Dean MP since 2005.