THERESA May launched a blistering attack on Brexit saboteur Tony Blair.

She accused the former Labour PM of insulting the British people with his shifty attempts to thwart the referendum result.

5 Theresa May has had a week of clashes with officials who have blocked her departure deal Credit: EPA

And she bluntly reminded him it was his own open-door immigration policy which spurred millions to vote leave.

Mrs May’s patience snapped after an exhausting week of clashes with MPs and Eurocrats blocking her departure deal.

In an astonishing broadside, she lashed out at her predecessor’s treacherous trip to meet EU chiefs in Brussels while Brexit talks were taking place.

She raged: “There are too many people who want to subvert the process for their own political interests – rather than acting in the national interest.

5 Tony Blair was reminded by the PM that it was his own open-door immigration policy which spurred millions to vote leave Credit: Getty Images - Getty

“For Tony Blair to go to Brussels and seek to undermine our negotiations by advocating for a second referendum is an insult to the office he once held and the British people he once served.

“We cannot, as he would, abdicate responsibility for this decision. Parliament has a democratic duty to deliver what the British people voted for.”

It was the second time in 24 hours that the livid PM has publicly berated Brexit wreckers.

On Friday she angrily confronted EU chief Jean-Claude Juncker after he branded her “nebulous”.

Prime Minister Theresa May explains what went down between her and Jean-Claude Juncker at the EU leaders summit centre in Brussels

Her outbursts follow a week in which she survived a no-confidence vote triggered by her own MPs – hours after abandoning a Commons vote on her deal to avoid humiliating defeat.

Mrs May will begin a massive arm-twisting exercise this week in a bid to win further concessions from the EU on the Irish border issue.

She will call the ambassadors of all 27 member states into 10 Downing Street to persuade them to deliver legally binding assurances that the backstop – which keeps Britain in a customs union – will be time-limited.

Top government lawyer Jonathan Jones will fly to Brussels for talks with his EU counterparts to seek written legal undertakings.

5 The PM accused Tony Blair of insulting the British people

The Sun on Sunday says FINALLY, some concrete planning for a clean-break Brexit. This week the jumped-up bureaucrats at the top of the Brussels tree proved that they simply aren’t interested in negotiating a good deal, for us or for them. They’d rather cut their nose off to spite their face, putting their ideological project ahead of the interests of their citizens. Even national leaders seem more interested in trying to trap us into an undemocratic second referendum than ensuring their businesses can freely trade with the fifth-largest economy in the world. The way Jean-Claude Juncker patronised the PM this week was an utter disgrace. We will be humiliated no more. When the clock strikes 11pm on March 29th next year, we WILL leave the European Union. And we must put every penny and pound we can into ensuring that our exit is as smooth as possible. The Brussels beast has wormed its way into just about every one of our institutions. Getting rid of it is going to take some work. But the predictions of apocalyptic job losses? Instant recession? We’ve heard the doomsday predictions before.

Wrong then, wrong now. There is one thing we are sure of, though, never more so than this week. If we believe in ourselves we have nothing to fear.

Mrs May hopes this will give her enough ammo to win MPs’ backing for her deal when they return from the festive break on January 7.

But with just 103 days until Brexit, she will press ahead with planning for a no-deal departure.

Foreign Secretary Jeremy Hunt yesterday urged colleagues to hold their nerve and prepare for leaving the EU without an agreement.

He said: “The deal on the table is what we have.

Hunt warns of 'real risks' if MPs reject Brexit deal

“But, the thing that the House of Commons will not accept is any risk of us being permanently trapped through the Northern Irish backstop in the customs union.

“I think it is possible to get this deal through with those guarantees that we need on the backstop.”

But he added: “The reason I think, in the end, the EU will want to help us as far as they possibly can is because it is not in their interest to provoke a further political crisis in the UK.

“Because, although some people in the EU may say that Parliament would stop a no-deal scenario, they can’t be sure of that.”

5 Theresa May has promised the public she will not disappoint with her Brexit deal Credit: AFP or licensors

Mrs May said she remains determined to see Brexit delivered and declared: “I will not let the British people down.”

She added: “I am fighting for a good deal for Britain. I will continue to fight for a good deal for Britain.

I have never lost sight of my duty and that is to deliver on the referendum result and to do so in a way that protects British jobs, keeps us safe and protects our precision Union.”

But her Cabinet is deeply divided over what their Plan B should be if the deal is voted down in the New Year – with some wanting a Norway-style deal and others prepared to leave without one. Fury is mounting over Philip Hammond who is now leaning towards backing a second referendum if other options fail. He is believed to be wooing four other ministers to back him.

5 Jeremy Hunt told his colleagues to prepare for leaving the EU without an agreement Credit: Reuters

The PM’s allies are also urging her to force a second referendum to defeat a “suicide squad” of Conservative Brexiteers attempting to bring down her government.

One Cabinet colleague said: “Phil has overstepped the mark once too often. Last week he went over the top with his remark about Brexit supporters being extremists and now this.

“If we had a second referendum, the party would be ripped to pieces. We were all elected on a manifesto to leave the EU and he seems determined to make an about turn on that.”

Former Cabinet minister Priti Patel said: “We need to bin the divisive and ill-thought-through Northern Ireland protocol. Signing up to anything that separates our union, and doesn’t provide a clear path to exit is unacceptable.

“There are clear alternatives. There is still time to negotiate a super Canada style trade deal without the divisive backstop. I urge the PM to grab this opportunity to pursue this and ensure we’re properly prepared for no deal.”

Nearly half of Brits believe Mrs May is brave and sticks to her principles, an Optimum poll revealed.

Tony Blair brands Brexit Britain 'a country in crisis' and pushes for 2nd referendum