United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Paul Hackett 

United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Paul Hackett 

United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Paul Hackett 

United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Peter Nicholls 

United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Peter Nicholls 

United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Peter Nicholls 

United Kingdom Independence Party (UKIP) MP Douglas Carswell leaves a television studio in central London, Britain March 25, 2017. Britain's UKIP party, widely credited as having been a major factor behind the country's decision to leave the European Union, lost its only lawmaker on Saturday when Douglas Carswell announced he was leaving the party. REUTERS/Peter Nicholls 

Nigel Farage (R), the leader of the United Kingdom Independence Party (UKIP) and Douglas Carswell, newly elected UKIP MP pose outside their office in Clacton-on-Sea in eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth/Files 

United Kingdom Independence Party MP Douglas Carswell arrives at the counting centre where he is fighting to keep his seat in Britain's general election, in Clacton, May 8, 2015. REUTERS/Neil Hall/Files 

Police officers escort Douglas Carswell, the United Kingdom Independence Party's only MP, after he was mobbed by demonstrators marching through Westminster during protest after the State Opening of Parliament in central London, Britain, May 27, 2015. REUTERS/Peter Nicholls

Police officers escort Douglas Carswell, the United Kingdom Independence Party's only MP, after he was mobbed by demonstrators marching through Westminster during protest after the State Opening of Parliament in central London, Britain, May 27, 2015. REUTERS/Peter Nicholls

Police officers escort Douglas Carswell, the United Kingdom Independence Party's only MP, after he was mobbed by demonstrators marching through Westminster during protest after the State Opening of Parliament in central London, Britain, May 27, 2015. REUTERS/Peter Nicholls

Police officers escort Douglas Carswell, the United Kingdom Independence Party's only MP, after he was mobbed by demonstrators marching through Westminster during protest after the State Opening of Parliament in central London, Britain, May 27, 2015. REUTERS/Peter Nicholls TPX IMAGES OF THE DAY

Nigel Farage, leader of the United Kingdom Independence Party (UKIP) (L), UKIP Party MP Douglas Carswell (C) and UKIP Deputy Chairman Suzanne Evans pose for a selfie outside 10 Downing Street in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

United Kingdom Independence Party (UKIP) MP Douglas Carswell poses in front of 10 Downing Street in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

Leanne Wood leader of Plaid Cymru (L) Natalie Bennett the leader of the Green Party (4th L), Nigel Farage, leader of the United Kingdom Independence Party (UKIP) (5th R), UKIP Deputy Chairman Suzanne Evans (2nd R) and UKIP Party MP Douglas Carswell (R) pose with other politicians in support of electoral reform outside 10 Downing Street in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

Nigel Farage, leader of the United Kingdom Independence Party (UKIP) (L) and UKIP Party MP Douglas Carswell pose after signing a petition in support of electoral reform outside the Houses of Parliament in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

Nigel Farage, leader of the United Kingdom Independence Party (UKIP) (L) and UKIP Party MP Douglas Carswell talk on Downing Street before submitting a petition in support of electoral reform in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

Nigel Farage, leader of the United Kingdom Independence Party (UKIP) and UKIP Party MP Douglas Carswell arrive at a publicity event to sign a petition in support of electoral reform outside the Houses of Parliament in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

Nigel Farage, leader of the United Kingdom Independence Party (UKIP) and UKIP Party MP Douglas Carswell arrive at a publicity event to sign a petition in support of electoral reform outside the Houses of Parliament in London, Britain May 18, 2015. REUTERS/Suzanne Plunkett 

United Kingdom Independence Party MP Douglas Carswell celebrates after retaining his seat, at a counting centre in Clacton, Britain May 8, 2015. REUTERS/Neil Hall

United Kingdom Independence Party MP Douglas Carswell celebrates after retaining his seat, at a counting centre in Clacton, Britain May 8, 2015. REUTERS/Neil Hall

United Kingdom Independence Party MP Douglas Carswell makes a speech after retaining his seat, at a counting centre in Clacton, Britain May 8, 2015. REUTERS/Neil Hall 

United Kingdom Independence Party MP Douglas Carswell and his wife Clementine arrive for the general election count in Clacton, Britain May 8, 2015. REUTERS/Neil Hall

United Kingdom Independence Party MP Douglas Carswell arrives at the counting centre where he is fighting to keep his seat in Britain's general election, in Clacton, May 8, 2015. REUTERS/Neil Hall 

United Kingdom Independence Party MP Douglas Carswell arrives at the counting centre where he is fighting to keep his seat in Britain's general election, in Clacton, May 8, 2015. REUTERS/Neil Hall 

Nigel Farage, the leader of the United Kingdom Independence Party, adjusts his hair as he walks with UKIP Member of Parliament Douglas Carswell to a campaign event in Clacton, Essex, April 13, 2015. REUTERS/Peter Nicholls

Nigel Farage, the leader of the United Kingdom Independence Party, laughs as he wears headphones, whilst UKIP Member of Parliament Douglas Carswell stands behind him during a visit to a factory in Clacton, Essex, April 13, 2015. REUTERS/Peter Nicholls

Nigel Farage, the leader of the United Kingdom Independence Party, laughs as he wears headphones, whilst UKIP Member of Parliament Douglas Carswell stands behind him during a visit to a factory in Clacton, Essex, April 13, 2015. REUTERS/Peter Nicholls

Mark Reckless (R), UKIP's second member of parliament, poses for a photo with Douglas Carswell, UKIP's first MP, outside St Stephen's entrance of the Houses of Parliament in Westminster, London, November 21, 2014. Prime Minister David Cameron's Conservatives lost a second parliamentary seat to the anti-EU UKIP party on Friday, an embarrassing defeat heralding a possible fragmentation of Britain's two-party system in next year's national election. Reckless was a Conservative lawmaker until he became the party's second member of the lower house of parliament to defect to UKIP, triggering Thursday's vote. His new party hopes his electoral success will spur other defections. REUTERS/Andrew Winning (BRITAIN - Tags: POLITICS TPX IMAGES OF THE DAY) 

Mark Reckless (R), UKIP's second member of parliament, poses for a photo with Douglas Carswell, UKIP's first MP, outside St Stephen's entrance of the Houses of Parliament in Westminster, London, November 21, 2014. Prime Minister David Cameron's Conservatives lost a second parliamentary seat to the anti-EU UKIP party on Friday, an embarrassing defeat heralding a possible fragmentation of Britain's two-party system in next year's national election. Reckless was a Conservative lawmaker until he became the party's second member of the lower house of parliament to defect to UKIP, triggering Thursday's vote. His new party hopes his electoral success will spur other defections. REUTERS/Andrew Winning (BRITAIN - Tags: POLITICS) 

Mark Reckless, UKIP's second member of parliament, is followed out of St Stephen's entrance of the Houses of Parliament by UKIP's first MP Douglas Carswell in Westminster, London, November 21, 2014. Prime Minister David Cameron's Conservatives lost a second parliamentary seat to the anti-EU UKIP party on Friday, an embarrassing defeat heralding a possible fragmentation of Britain's two-party system in next year's national election. Reckless was a Conservative lawmaker until he became the party's second member of the lower house of parliament to defect to UKIP, triggering Thursday's vote. His new party hopes his electoral success will spur other defections. REUTERS/Andrew Winning (BRITAIN - Tags: POLITICS) 

Mark Reckless, UKIP's second member of parliament, poses for a photo as Douglas Carswell, UKIP's first MP, photographs him with his telephone outside St Stephen's entrance of the Houses of Parliament in Westminster, London, November 21, 2014. Prime Minister David Cameron's Conservatives lost a second parliamentary seat to the anti-EU UKIP party on Friday, an embarrassing defeat heralding a possible fragmentation of Britain's two-party system in next year's national election. Reckless was a Conservative lawmaker until he became the party's second member of the lower house of parliament to defect to UKIP, triggering Thursday's vote. His new party hopes his electoral success will spur other defections. REUTERS/Andrew Winning (BRITAIN - Tags: POLITICS) 

Mark Reckless (R), UKIP's second member of parliament, poses for a photo with Douglas Carswell, UKIP's first MP, outside St Stephen's entrance of the Houses of Parliament in Westminster, London, November 21, 2014. Prime Minister David Cameron's Conservatives lost a second parliamentary seat to the anti-EU UKIP party on Friday, an embarrassing defeat heralding a possible fragmentation of Britain's two-party system in next year's national election. REUTERS/Andrew Winning (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage arrives at the Houses of Parliament in London October 13, 2014. Newly elected UKIP MP Douglas Carswell took his seat in the House of Commons for the first time on Monday. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage speaks to the media as he arrives at the Houses of Parliament in London October 13, 2014. Newly elected UKIP MP Douglas Carswell took his seat in the House of Commons for the first time on Monday. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage speaks to the media as he arrives at the Houses of Parliament in London October 13, 2014. Newly elected UKIP MP Douglas Carswell took his seat in the House of Commons for the first time on Monday. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell poses for the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell poses for the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell speaks to the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell poses for the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell poses for the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS TPX IMAGES OF THE DAY) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell poses for the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell poses for the media as he arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS) 

Newly elected United Kingdom Independence Party (UKIP) MP Douglas Carswell arrives at the Houses of Parliament in London October 13, 2014. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage (C) speaks alongside former Conservative MP and UKIP candidate Mark Reckless (L) and newly elected UKIP MP Douglas Carswell (R) outside the party campaign office in Rochester southeast England October 11, 2014. Farage was in Rochester to campaign for Conservative defector Mark Reckless who's departure from the Conservative Party to join UKIP sparked a by-election in his Rochester and Strood constituency. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage (2L) reacts with former Conservative MP and UKIP candidate Mark Reckless (L) and newly elected UKIP MP Douglas Carswell (3L) outside the party campaign office in Rochester southeast England October 11, 2014. Farage was in Rochester to campaign for Conservative defector Mark Reckless who's departure from the Conservative Party to join UKIP sparked a by-election in his Rochester and Strood constituency. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage (2L) reacts with former Conservative MP and UKIP candidate Mark Reckless (L) and newly elected UKIP MP Douglas Carswell (3L) outside the party campaign office in Rochester southeast England October 11, 2014. Farage was in Rochester to campaign for Conservative defector Mark Reckless who's departure from the Conservative Party to join UKIP sparked a by-election in his Rochester and Strood constituency. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

United Kingdom Independence Party (UKIP) leader Nigel Farage (2L) reacts with former Conservative MP and UKIP candidate Mark Reckless (L) and newly elected UKIP MP Douglas Carswell outside the party campaign office in Rochester southeast England October 11, 2014. Farage was in Rochester to campaign for Conservative defector Mark Reckless who's departure from the Conservative Party to join UKIP sparked a by-election in his Rochester and Strood constituency. REUTERS/Luke MacGregor (BRITAIN - Tags: POLITICS) 

Newly elected UK Independence Party (UKIP) MP Douglas Carswell speaks to members of the media in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Nigel Farage (R), the leader of the United Kingdom Independence Party (UKIP) and Douglas Carswell, newly elected UKIP MP pose outside their office in Clacton-on-Sea in eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected UK Independence Party (UKIP) MP Douglas Carswell gestures outside their office in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Nigel Farage (R), the leader of the United Kingdom Independence Party (UKIP) and Douglas Carswell, newly elected UKIP MP pose outside their office in Clacton-on-Sea in eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected Independence Party (UKIP) MP Douglas Carswell speaks with a bus driver in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected Independence Party (UKIP) MP Douglas Carswell takes a selfie photograph in front of photographers in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected Independence Party (UKIP) MP Douglas Carswell takes a selfie photograph in front of photographers in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected UK Independence Party (UKIP) MP Douglas Carswell gestures outside their office in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected UK Independence Party (UKIP) MP Douglas Carswell holds a newspaper showing his election, in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS) 

Newly elected UK Independence Party (UKIP) MP Douglas Carswell gestures outside their office in Clacton-on-Sea, eastern England October 10, 2014. Britain's anti-EU UK Independence Party won its first elected seat in parliament on Friday by a landslide and came a close second in another vote, proving it poses a threat to the country's two main parties in a national election next year. REUTERS/Stefan Wermuth (BRITAIN - Tags: POLITICS ELECTIONS)