Tory MP Douglas Carswell revealed he had not told David Cameron he was defecting to Ukip.
Carswell "I've not yet spoken to the Prime Minister...if I'd phoned him up beforehand you'd have heard about it in another way"
The Prime Minister and Mr Carswell's relationship has not always been friendly, with Mr Cameron once telling the Clacton MP he needed to "get a sense of humour".
ITV News Political Correspondent Paul Brand is following updates from the special Ukip press conference at which Mr Carswell is speaking.
Carswell says he thinks members of his local party will come with him. But feels sad to be leaving them.
More top news
During their visit, Charles and Camilla will meet local businesses and people in the city centre before joining a reception in the Guildhall
The United Kingdom is on course to leave the European Union next year.
The European Research Group chair said the chances of Brexit in Name Only have been ‘significantly reduced’.