Theresa May is expected to appoint an EU ambassador who “believes in Brexit” in the wake of the current Brussels representative's decision to quit after being cut adrift by Downing Street.

Sir Ivan Rogers on Tuesday announced his resignation as Britain’s ambassador in Brussels after it was made clear Mrs May and her senior team had “lost confidence” in him over his “pessimistic” view of Brexit.

Government sources made clear that Sir Ivan had “jumped before he was pushed” and that Number 10 believed his negative view of Brexit meant that he could not lead the negotiations after the Prime Minister triggers Article 50.

In a 1,400-word resignation letter to his staff leaked on Tuesday night, Sir Ivan launched a thinly-veiled attack on the "muddled thinking" in Mrs May's Government.