How to become British Prime Minister in a week

London. It took ousted British Prime Minister Liz Truss eight-and-a-half weeks to win the keys to 10 Downing Street. Her successor will achieve the same feat in a matter of days.

This time the process of electing the party's new leader -- who will automatically become prime minister -- is being accelerated to last a week at most.

It will come in stark contrast to the contest that led to Truss becoming prime minister.

After predecessor Boris Johnson announced on July 7 that he intended to resign, it was not until September 5 that the decisive result of an online ballot was announced.

That was the culmination of a lengthy process that began with MPs voting for their preferred candidate, who was not Truss.

She was only won after members of the party -- who under Conservative rules get the final say when multiple candidates remain -- backed the now ex-premier many weeks later.

The late Queen Elizabeth II then confirmed her in the job.

This time, the process will be condensed into one week and possibly even faster.

Each candidate must gain the support of 100 MPs by 2:00 pm (1300 GMT) on Monday, according to Graham Brady, chairman of the 1922 Committee of Conservative backbenchers which will oversee the contest.

Nominations opened late Thursday. Given that the party has 357 MPs in parliament the field will necessarily be limited to a maximum of three candidates.

So far there are no formal contenders, but the contest is widely expected to be a race between Johnson, former finance minister Rishi Sunak and senior cabinet member Penny Mordaunt

Members' final say?

A first vote will take place at 3:30 pm on Monday, with the result announced at 6:00 pm.

If there are three candidates, the one with the fewest votes will be eliminated.

The final two will then face a second round, intended to establish the preferred choice of MPs, with that result announced at 9:00 pm.

At this stage, the candidate with the lowest tally could drop out, as happened when Theresa May became prime minister in 2016.

In this scenario, the single remaining candidate automatically becomes party leader and prime minister.

If two candidates remain, they will be put to an online ballot of party members with the result announced on October 28.

At least one televised debate involving any final pair would be expected to take place next week.

In the event of no run-off, party members would be denied their usual final say, a key factor in the election of Truss who was more popular with party members than the parliamentary party.

In the final round of voting by MPs, Sunak secured 137 votes to Truss's 113, making him the preferred choice of parliamentarians. Mordaunt, who was the other candidate, secured 105 votes.

When the final two candidates were put to a membership ballot, in which nearly 142,000 out of around 170,000 party members took part, Truss won 57 percent of the vote against Sunak's 43 percent.