The former SAS reservist who failed in his Tory leadership bid
He was understood to have serious reservations about both the plan and whether it could be acceptable to Brussels.
David Davis has quit his role as Brexit Secretary less than two years after his appointment.
His resignation is a major blow to Prime Minister Theresa May and comes after he signed up to the Brexit plan agreed by the Cabinet at Chequers on Friday.
He was understood to have serious reservations about both the plan and whether it could be acceptable to Brussels.
– Here is a look at the career of the long-standing Eurosceptic, 69, who readily admitted to having been branded a “charming bastard”.
Mr Davis was elected for Haltemprice and Howden in 1997, having originally sat for Boothferry since 1987.
The married father-of-three first honed his negotiating skills in the cut-throat world of big business.
He enjoyed corporate success in his thirties as a director of Tate and Lyle and President of Zymaize, a loss-making Canadian sweetener manufacturer which he turned into a gold mine.
Mr Davis became politically active as a student, cutting an imposing figure even then as chairman of the Federation of Conservative Students.
A man with brawn as well as brains, he served as an SAS reservist to help fund himself through college, before entering Parliament in 1987.
He had a tough upbringing by a single mother in a Labour working-class household in south London, and still bears the scar on his upper lip from a crowbar attack in Brixton.
The two-time unsuccessful Conservative leadership contender gained a fearsome reputation after taking a series of ministerial scalps in a previous role of shadow home secretary.
Among those he claims as his victims are former home secretaries David Blunkett and Charles Clarke and ex-home office minister Beverley Hughes.
He was regarded by many as the likely next Tory leader after Michael Howard announced he was to resign, but after a weak campaign – in his second tilt at the leadership – he was soundly beaten in 2005.
His rival, David Cameron, had caught the mood with his careful presentation and youthful optimism.
In the 2001 leadership contest, Mr Davis cut his losses and quit after twice finishing way down the pack in early ballots of Tory MPs, throwing his support behind Iain Duncan Smith.
The contest successfully raised his profile and Mr Duncan Smith appointed him party chairman.
A libertarian who was never afraid to speak his mind, even if his opinions fell outside the party line, he worked closely with former Liberty director Shami Chakrabarti.
Mr Davis once revealed that he offered to buy Mr Campbell’s old newspaper the Daily Mirror so the former journalist could edit it.
He put their unlikely friendship down to his liking for ”strong mavericks” and there is something of that description in him.
Despite Eurosceptic views, he acted as a whip for John Major during the bruising battle to ratify the Maastricht Treaty.
Mr Davis has previously listed mountaineering, parachuting and flying light aircraft among his more athletic pursuits.