It has been suggested that before his defection, Mr Carswell was shown polling telling him he would be more likely to be re-elected if he stood as an MP for Ukip. Mr Carswell has claimed he quit the Tory party because of Mr Cameron’s European Union policies, despite previously saying the only way to get a referendum was to vote Conservative. Other Tory MPs, including Philip Hollobone, are thought to have been targeted by Ukip officials.