WARRINGTON North MP Helen Jones has asked whether the reason Boris Johnson ruled himself out of the Tory leadership race is 'because he won't take the pay cut'.

The confirmed candidates battling to be the next Conservative leader and Prime Minister are justice secretary Michael Gove, home secretary Theresa May, energy minister Andrea Leadsom, work and pensions secretary Stephen Crabb and former defence secretary Liam Fox.

The leadership battle comes following the resignation of PM David Cameron after the UK voted to leave the EU last Thursday.

Mr Johnson, who joined Warrington South MP David Mowat for a Stockton Heath visit one week before last year's General Election, had been expected to officially launch his leadership campaign in London earlier today, Thursday.

But the Uxbridge and South Ruislip MP stunned the nation with a speech confirming he would not be standing as a candidate, with many speculating about the reasons behind the announcement.

Mrs Jones was one of those to comment on the situation.

She tweeted: "Is #Boris not standing because he won't take the pay cut?"

The new PM is in line to receive £143,462, which includes the parliamentary salary of £74,962.

Despite the shock announcement from Mr Johnson today, at the start of the week the town's former Tory leader Paul Kennedy told the Warrington Guardian that he felt it was not in the MP's 'interests to put himself up' for the contest.

He said: "Often, success in politics is a question of timing and luck.

"While he might be popular in local Conservative associations, I am not convinced he is as popular as he was in the country as a whole."

Mr Kennedy added that he felt the speech was 'very good in the circumstances'.

The winner of the Tory contest is expected to be announced on September 9.