BORIS Johnson received rapturous applause at the Tory conference as he denounced Theresa May’s plan for EU withdrawal as an “outrage” and called on activists to persuade her to “chuck Chequers”.

Speaking at a packed fringe meeting at the event, the former foreign secretary won an enthusiastic reaction on a scale not seen so far inside the main hall.

READ MORE: Tory members turn out for Boris Johnson's speech over panel discussion focused on the Union

His intervention immediately renewed speculation about a leadership challenge and put the Prime Minister under increased pressure when she addresses the gathering today.

May lost no time in hitting back at Johnson in a series of interviews after his speech as the internal feud between the two intensified.

She accused him of threatening the future of the UK by dismissing the so-called “backstop” arrangement designed to maintain an open border between the Republic and Northern Ireland regardless of the outcome of the Brexit negotiations.

Speaking to ITV, May said: “What he appeared to be saying was he wanted to tear up something which was effectively a guarantee to the people of Northern Ireland. I believe as a Unionist that it is important that we recognise the needs and concerns of people in Northern Ireland.”

In a separate interview with the BBC, the Prime Minister said: “Well there are one or two things that Boris said that I am cross about. He wanted to tear up our guarantee to the people of Northern Ireland.”

Johnson left the venue in a media scrum facing questions about whether he had been setting out his vision for the leadership.

And earlier Scottish Tory Ross Thomson was among the close supporters accompanying Johnson as he arrived to give his speech. The Aberdeen South MP was photographed with his arm shielding the ex Cabinet minister – despite suggestions Scottish Conservatives were leading the charge against Johnson becoming Prime Minister.

One report said the party north of the Border had launched a secret campaign codenamed “Operation Arse” to stop Johnson becoming leader amid fears he would leave the Scottish party again with just a single MP.

During his speech Johnson urged Tory delegates to return to the hard Brexit blueprint the Prime Minister first set out in her Lancaster House speech, when she said she would take the UK out of the customs union, single market and jurisdiction of the European Court of Justice.

He even won loud applause when he suggested the PM risked being prosecuted under a 14th century law saying that “no foreign court or government shall have jurisdiction in this country”. He rejected as “total fantasy” the idea it would be possible to “bodge” Brexit now and then negotiate a better deal after leaving in March 2019. And he warned if a deal based on Chequers was agreed with the EU, it would “embolden” those calling for a second referendum – something he said would be “disastrous for trust in politics”.

Johnson said May’s blueprint – which ties Britain to a common rulebook with the EU for trade in goods – would be “humiliating for a £2 trillion economy” and would prevent the UK from making its own laws and subject it to the directives of Brussels.

“This is not pragmatic, it is not a compromise. It is dangerous and unstable – politically and economically,” he said. “My fellow Conservatives, this is not democracy. This is not what we voted for. This is an outrage. This is not taking back control: this is forfeiting control”. And he warned: “If we get it wrong – if we bottle Brexit now – believe me, the people of this country will find it hard to forgive. “For one last time, I urge our friends in Government to deliver what the people voted for, to back Theresa May in the best way possible – by softly, quietly, and sensibly backing her original plan ... Because if we get it wrong we will be punished. And if we get it right we can have a glorious future.”