Patrick Mercer, the MP who has quit the Tories after a lobbying sting, is a former soldier and journalist - including for the Daily Telegraph - who became a fierce critic of David Cameron's leadership.
He was the first Tory MP to be named as having written to party chiefs, calling for the Prime Minister to quit.
And in 2010 he had to resign from the front-bench position of shadow homeland security spokesman after claiming he had met "a lot" of "idle and useless" ethnic minority soldiers who used racism as a "cover", while also saying it was a normal part of Army life to be called a "black bastard".
He later said he "deeply" regretted any "offence" he had caused.
According to his profile on the Conservative Party website, Mercer was born in 1956, the son of an Anglican Bishop.
After leaving Oxford University, he joined the Army, spending most of his service in Northern Ireland, but also Germany, Canada, Uganda, Brunei and the Balkans, and was given an OBE in 1996 for service in Bosnia.
After leaving the Army in 1999, he became a defence correspondent for BBC Radio 4's Today programme, later working as a freelance journalist for the Telegraph.
He won his home-town seat of Newark in Nottinghamshire in 2001, and had a majority of more than 16,000 at the last General Election.
Since being elected, he has championed the rights of homeowners to protect themselves against burglars, after the case of farmer Tony Martin in his constituency.