JOHNSON THE FAVOURITE

Surveys have suggested that the members are overwhelmingly pro-Brexit and in favour of leaving the EU without a deal.

Boris Johnson is the clear favourite with bookmakers and he has also said Britain should be prepared to exit the bloc without any deal if no acceptable agreement could be reached.

"We will leave the EU on October 31, deal or no deal," Johnson told an economic conference in Switzerland on Friday.

The party's divisions over the EU has led to the demise of its last four prime ministers - May, Cameron, John Major and Margaret Thatcher - and there is little indication these schisms will be healed soon.

"There are huge tensions in this race which are that people will be encouraged to promise things they can't deliver, of those probably the most dramatic are people who are going to be encouraged to promise a no-deal Brexit," one of the contenders, Rory Stewart, told BBC radio.

While parliament repeatedly rejected May's accord, lawmakers have also previously voted against leaving without any deal.

Stewart said he could not serve in a Johnson government that was prepared to accept a no-deal Brexit.