Mr Johnson’s victory in the Tory leadership contest was confirmed just after midday when he vowed to “deliver Brexit, unite the party and defeat Jeremy Corbyn”. Mr Corbyn 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.”
He continued: “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.”
Shadow chancellor John McDonnell tweeted: “This first Johnson speech is excruciatingly and embarrassingly underwhelming.
“It was a like an ill prepared after dinner speech at the local golf club.”
Shadow justice secretary Richard Burgon tweeted: “Trumpism comes to the UK.
“Johnson will scapegoat and whip up division to protect an economic system rigged for billionaires.
“The priority now for all progressives is to make him the shortest-serving PM in history, beat his hard-right no Deal plans and get Jeremy Corbyn into Number 10.”
New 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. It’s the Liberal Democrats who can lead the renewal our country needs.”
SNP leader Nicola Sturgeon has insisted Scotland must have the right to determine its own future as she highlighted “profound concerns” about the new Conservative leader.
Ms Sturgeon made it clear she would “oppose his threat of a no deal Brexit” and also pledged to “do everything possible to ensure that he respects Scotland’s views and interests”.