Tory MPs will begin the process of voting for a new leader on Wednesday, with Boris Johnson's successor to be finally announced on 5 September.

Following a meeting of the 1922 Committee executive, chairman Graham Brady said nominations will open and close tomorrow.

In order to stand, a candidate will need the support of 20 MPs - potentially making it harder for some of the less well-known contenders to make it onto the ballot paper.

The first ballot of MPs will then take place on Wednesday, with any candidate who fails to get at least 30 votes expected to drop out.

A second ballot will follow on Thursday with further ballots to be held next week until the list of candidates is whittled down to a final two - who will go forward into a postal ballot of party members.

Mr Brady said the final result would be announced on 5 September, when MPs return to Westminster following their summer break.

He said it was a "perfectly reasonable" timetable that would allow hustings to take place around the country over the summer.

It comes after the outgoing British Prime Minister said he is "determined" to deliver the mandate he was elected on in 2019, in his first public appearance since he resigned as Conservative leader.

Speaking during a visit to the Francis Crick Institute in London, he told reporters: "I'm determined to get on and deliver the mandate that was given to us, but my job is really just to oversee the process in the next few weeks, and I’m sure that the outcome will be good.

"We just need to get on and as I said I think before to you, the more we focus on the people, on the people who elect us, on their jobs, their hopes and what they can get out of investment in science and technology.

"The more we talk about the the future that we’re trying to build, the less we talk about politics in Westminster, the generally happier we will all be."

Mr Johnson refused to speak about the mass exodus of his ministers that led to his resignation last week and said throwing his weight behind one of the candidates to succeed him could "damage" their chances.

Following the accusation in his resignation speech that his tormentors had succumbed to a "herd mentality", he was asked whether he felt betrayed.

Mr Johnson said: "I don't want to say any more about all that.

"There’s a contest under way and it’s happened, and, you know, I wouldn’t want to damage anybody’s chances by offering my support.

"I just have to get on and, in the last few days or weeks of the job, the constitutional function of the prime minister in this situation is to discharge the mandate, to continue to discharge the mandate, and that’s what I’m doing.

"I think the reason we’re here today is because I think … science, technology – our natural genius in this area is one of the many, many things that is going to carry us forward and make sure that our our future is very bright."

Former finance minister Rishi Sunak is regarded as the current front runner with foreign minister Liz Truss announcing her candidacy overnight.

Ms Truss has launched her campaign with a pledge for "low taxes" and a "firm grip on spending".

In a video posted to Twitter with the tagline "Trusted to deliver", she said a prime minister with "experience, who can hit the ground running from day one" is needed.

She highlighted her work on trade deals with Australia and Japan and on the controversial Northern Ireland Protocol Bill as among her credentials.

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Other contenders include former health ministers Sajid Javid and Jeremy Hunt, Mr Sunak's successor Nadhim Zahawi, transport minister Grant Shapps and trade minister Penny Mordaunt.

Fellow candidate and senior backbencher Tom Tugendhat, Mr Hunt and Mr Zahawi have all pledged to cut taxes.

Mr Hunt said today that he wants to "cut all taxes" and that reducing Government department running costs is "something we should always be looking at".

Mr Hunt, who has proposed cutting corporation tax to 15%, told BBC Breakfast: "We need to have a lower tax environment to help businesses get off the ground."

His rival, Mr Zahawi, has said he would force every Government department to cut running costs by 20% to fund tax cuts.

The newly-appointed Chancellor told Sky News that he managed to reduce costs at the Education Department by close to 20%.

Mr Tugendhat has said he would "lower taxes across every aspect of society".

The Foreign Affairs Committee chair noted he was one of a few Conservative MPs to vote against the national insurance "tax on jobs" hike.

Attorney General Suella Braverman, former minister Kemi Badenoch and newly appointed Foreign Office minister Rehman Chisti have also thrown their hats into the ring.

Ms Braverman has said she would amend the Northern Ireland Protocol Bill to set VAT, excise and the regulation of medicines directly under UK law from day one.

She has also pledged to move to remove new EU laws from applying to Northern Ireland.

The Attorney General said in a statement: "The Northern Ireland Protocol was never meant to be a permanent solution.

"As prime minister, I would make the changes to the NIP Bill that I've been arguing for within government, to make it fully compliant with UK sovereignty.

"That means from day one after the Bill becomes law, the EU would have no more say over VAT and Excise in Northern Ireland and no say in our regulation of medicines.

"After my changes, UK law - and tax rates - would apply directly".

Former Cabinet minister Michael Gove - who was dramatically sacked by Mr Johnson last week - pledged his support for Ms Badenoch, while Work and Pensions Secretary Therese Coffey said she would back Ms Truss.

Andrea Leadsom, who has contended for the Tory leadership in the past, endorsed Ms Mordaunt.