Boris Johnson will be the UK's next Prime Minister after he resoundingly defeated Jeremy Hunt to claim the Conservative party leadership in a landslide.

The former London mayor was victorious over Hunt with 92,153 votes (66%) to the foreign secretary's 46,656 (34%) in the ballot of Tory party members.

Johnson has pledged to take Britain out of the European Union by the next Brexit deadline of October 31 "come what may".

The leadership result was announced just before midday on Tuesday in London, with Conservative officials announcing a 87% turn-out.

The contest was triggered after Theresa May announced her resignation, following successive Commons defeats of her Brexit deal.

Tory MPs whittled the field of contenders down from ten to two, with Johnson and Hunt then taking part in a series of hustings around the country, including one in Scotland.

Johnson has pledged to set up a unit in Downing Street to "sense-test and stress-test" the impact of his government's policies on the union.

He is the 20th British Prime Minister to have been educated at the elite Eton college near Windsor, and the third Conservative PM since 2010.

After Theresa May takes part in her final Prime Minister's Questions on Wednesday, she will travel to Buckingham Palace to formally tender her resignation to the Queen.

Johnson will then visit the palace and be invited to form a government, entering Downing Street later in the day.

Speaking after the result, Johnson said it was not irreconcilable to remain close with the EU and to deliver Brexit.

He said: "Today at this political moment in our history we again have to reconcile two sets of instincts, two noble sets of instincts, between the deep desire of friendship and free trade and mutual support in security and defence between Britain and our European partners and the simultaneous desire, equally deep and heartfelt, for democratic self-government in this country.

"Of course some people would say that they are irreconcilable and it just can't be done."

He said he read in the Financial Times this morning that no incoming leader has ever faced "such a daunting set of circumstances".

Johnson continued: "Well I look at you this morning and I ask myself, 'Do you look daunted? Do you feel daunted?' I don't think you look remotely daunted to me.

"I think we know that we can do it and that the people of this country are trusting in us to do it and we know that we will do it."

Johnson pledged to "deliver Brexit, unite the country and defeat Jeremy Corbyn", repeating key lines from his campaign stump speech.

He told the audience: "I know some wag who has already pointed out that deliver, unite and defeat was not the perfect acronym for an election campaign since unfortunately it spells dud.

"But they forgot the final E my friends, E for energise.

"And I say to all the doubters, 'Dude we are going to energise the country, we are going to get Brexit done on October 31, we are going to take advantage of all the opportunities that it will bring in a new spirit of can do."

He vowed to improve education, boost infrastructure, put more police on the streets and bring in full-fibre broadband across the UK.

"We are going to unite this amazing country and we are going to take it forward," the Tory leader said.

Responding to Johnson's victory, First Minister Nicola Sturgeon said it highlighted "the need for Scotland to have the right to determine our own future".

"I congratulate Boris Johnson on his election as Tory leader and I will do everything possible to ensure that he respects Scotland's views and interests," the First Minister said.

"However, I have profound concerns about the prospect of his premiership and it would be hypocritical not to be frank about these.

"These are concerns that I am certain will be shared by the vast majority of people in Scotland who, had they been given any say, would not have chosen to hand the keys of Number 10 to someone with his views and track record."

She continued: "Brexit of any kind would be deeply damaging to Scotland and the rest of the UK, but his public pledge to leave the EU by October 31 - 'come what may' and 'do or die' - flies in the face of logic, common sense or any basic regard for the wellbeing of the people and nations of the UK.

"It is a deeply irresponsible threat, and not once that should be contemplated by any serious political leader.

"It should now be taken off the table without delay or equivocation."

Sturgeon added: "Scotland did not vote for Brexit, or for the current Tory government - and certainly not for Boris Johnson as Prime Minister.

"All of this underlines the need for Scotland to have the right to determine our own future."

Jeremy Corbyn used the result to reiterate his longstanding call for a general election.

The Labour leader tweeted: "Boris Johnson has won the support of fewer than 100,000 unrepresentative Conservative party members by promising tax cuts for the richest, presenting himself as the bankers' friend, and pushing for a damaging no-deal Brexit.

"But he hasn't won the support of our country.

"Johnson's no-deal Brexit would mean job cuts, higher prices in the shops, and risk our NHS being sold off to US corporations in a sweetheart deal with Donald Trump.

"The people of our country should decide who becomes the Prime Minister in a general election."

Newly-elected Liberal Democrat leader Jo Swinson said: "Boris Johnson has finally got his hands on the keys to Number 10, but he has shown time and time again that he isn't fit to be the Prime Minister of our country.

"Whether it is throwing people under the bus or writing a lie on the side of one: Britain deserves better than Boris Johnson.

"If we want to defeat nationalism and populism, we need to give people an alternative vision for our country."

Brexit party leader Nigel Farage said: "I wish Boris Johnson well as Prime Minister with his do or die pledge to deliver Brexit on October 31. Does he have the courage to deliver?"

Scottish secretary David Mundell, who has been critical of Johnson in the past, said: "I congratulate Boris Johnson on his clear win in the leadership contest.

"Our party must now unite behind the new leader and Prime Minister, so we can get on with the job of delivering Brexit, whilst maintaining a strong United Kingdom."

Abroad, the incoming PM has been congratulated by US president Donald Trump.

The president tweeted: "Congratulations to Boris Johnson on becoming the new Prime Minister of the United Kingdom. He will be great!"

The European Commission's Brexit negotiator Michel Barnier said: "We look forward to working constructively w/ PM Boris Johnson when he takes office, to facilitate the ratification of the Withdrawal Agreement and achieve an orderly Brexit.

"We are ready also to rework the agreed declaration on a new partnership in line with EUCO guidelines."