BORIS Johnson’s campaign to become Conservative Party leader and the next Prime Minister is struggling to gain traction in Sussex.

Shortly after the 24-hour window for nominations opened yesterday, Lewes MP Maria Caulfield – a fellow Leave campaigner alongside Mr Johnson ahead of the referendum – endorsed underdog candidate Stephen Crabb.

She backed him for “wanting to do something, not be someone”.

Meanwhile, Sir Peter Bottomley, MP for Worthing West, indicated that he hoped the victor would not be drawn from the current front-runners – an indication that he will not be supporting Mr Johnson.

On Tuesday Nicholas Soames, MP for Mid Sussex, endorsed Mr Johnson by tweet but yesterday Sir Peter Bottomley told The Argus: “We know that some of the most successful and important Prime Ministers were not obvious before a contest.

“They include Winston Churchill, Margaret Thatcher, John Major and David Cameron. I trust we are as fortunate this year.”

In a statement, Ms Caulfield endorsed Mr Crabb, who was promoted to the rank of Secretary of State for Work and Pensions following the resignation of Iain Duncan Smith in March.

She said: “Like myself, Stephen Crabb grew up on a council estate and has had to work hard to get to the position in which he now finds himself.

“When you listen to him he talks about his vision for our country, a vision which sees hope and a way forward for those who feel left behind by the state, those who feel the economic recovery of this country has passed them by and those who, last week, voted to leave the EU because they have not felt the benefits of being in the European Union.

“This is a man who wants to do something and not just be someone.”

Under Conservative Party leadership election rules, MPs must vote on a list of nominated candidates among themselves before allowing the party membership to choose between the two front runners.

Unlike in last year’s Labour Party leadership election, it is not possible to sign up to the party to influence the vote: only those who were members before June 2 of this year will be eligible to cast a ballot.

Yesterday in the House of Commons outgoing Prime Minister David Cameron seemed to display uncharacteristic emotion at the dispatch box as he claimed it was not in the national interest for under-fire Labour leader Mr Corbyn to remain in post, saying: “For heaven’s sake man, go.”

Mr Crabb is the only person formally to have announced his candidature so far but Boris Johnson is believed to have the support of more than 100 Tory MPs and Home Secretary Theresa also has strong support.