Britain's next Prime Minister will be chosen in a completely new way

For the first time in history, Britain's Prime Minister will not be chosen by a general election, or by MPs, but by party activists - as the New Statesman reported back in February.

Prime Minister David Cameron announced his resignation this morning, after Britain voted to leave the EU against his wishes.

"We should have a new Prime Minister in place by the Conservative party conference in October," Cameron said.

The new Prime Minister will be chosen by a Conservative party leadership election.

This election will have two parts:

• Firstly, Conservative MPs elect two candidates.
• After these two candidates have been chosen, a postal ballot will be sent out to all Conservative party members, on a "one member, one vote" basis.

The winner of this vote will then become the next Prime Minister. That means that 149,800 Tory activists (according to the latest House of Commons Library data) - around 0.002% of the UK population - will choose the next leader of the UK.

Who is in the running to become the new prime minister?

One of the figure heads of the leave campaign, Boris Johnson, is the bookies favourite to become the next leader of the Conservative Party - currently at 8/13 on Betfair.

However, as we saw during the announcement of the referendum results, the bookmakers do not have a crystal ball.

Nevertheless, as a result of the momentum of the referendum result and strong anti-EU fervour among the Conservative activists eligible to vote in the leadership election, it seems likely that a pro-Brexit Conservative will become the next Prime Minister.

Other successful proponents of the Leave campaign Michael Gove and Andrea Leadsom are also believed to have a good chance at landing the top job. However, Gove has previously ruled out running to become leader of the Tory party, according to The Telegraph.

Theresa May, who backed Remain, but was relatively restrained during the campaign, is the second favourite to become Conservative leader, at 3/1 on Betfair.