A former Treasurer of the Conservative Party has joined UKIP following David Cameron's decision to rule out a referendum on whether Britain should stay in the EU.
Lord Alexander Hesketh is the most senior Conservative Party politician to date to join UKIP.
He had held a number of positions within the governments of Margaret Thatcher and John Major, including Parliamentary Under-Secretary of State - Department of Environment (1989-1990) and Minister of State - Department of Trade and Industry (1990-1991).
In May 1991 he was appointed Chief Whip in the House of Lords by John Major, a position he held for nearly two-and-a-half years.
He was Treasurer of the Conservative Party between 2003 and 2004. Between 2003 and 2010 he was Chairman of the Conservative Party Foundation.
Outside of politics, Lord Hesketh has a love of motor racing and in 1972 launched Hesketh Racing which saw success in Formula One between 1973 and 1978 with British racing driver James Hunt. He also founded Hesketh Motorcycles which set up a purpose built factory in Daventry in 1982 to build the Hesketh V1000 motorcycles. In 1994 Lord Hesketh helped set up British Mediterranean Airways (BMED) and served as Executive Chairman of the new airline. In 2007, BMED was purchased by BMI.
Lord Hesketh is the owner and executive chairman of Towcester racecourse. He also serves as an independent director of Air Astana, the national carrier of Kazakhstan.
In November 2010 he resigned from his position as Deputy Chairman at engineering group Babcock International after saying that the Royal Navy's aircraft carrier programme was "about to turn into a classic British disaster". Babcock is building the carriers at its shipyard in Rosyth.
Lord Hesketh was reported as saying a quicker and cheaper solution would have been to adapt the RAF's current fleet of Typhoon aircraft for work at sea, but he claimed this was less lucrative for BAE.
He had held the position of Deputy Chairman for fourteen years, before which he was a non-executive for three years.
Lord Hesketh will be launching a fundraising club for UKIP and will be acting as a spokesman on matters of defence procurement.
Lord Hesketh said: "I have been a Conservative all my adult life but the recent decision by the Prime Minister to rule out a referendum on EU membership has angered me greatly. On this, and many other matters, UKIP's views chime with mine and I am delighted to join the party which is fast becoming a real force in British politics."
Nigel Farage, UKIP Leader, said: "Lord Hesketh brings a wealth of political experience to UKIP and he is warmly welcomed to the party.
"Over the last few months a number of former Conservatives have joined UKIP as they have become disillusioned with the Conservative Party. Lord Hesketh felt let down by David Cameron when he recently ruled out a referendum and he is not alone.
"The Prime Minister is not only letting down his party, but millions of people across the UK who just want to have their say on future EU membership. On matters of defence, Lord Hesketh's expertise and knowledge is second to none and he will be a valuable addition to our policy team."