THERESA May will attend church this morning before retiring to her country retreat at Chequers.

No doubt she will take one of her long walks as she prepares to face the toughest week of her political life.

3 If Theresa May faces a vote of no confidence, Corbyn would be PM within weeks Credit: AFP - Getty

But on her trek around the gardens one thing should focus her mind above all others.

The prospect of Jeremy Corbyn in Downing Street within weeks.

Of all the outcomes of the Brexit fiasco, the most disastrous by far would be ushering into Number 10 a man who would do untold damage to Britain.

It seems almost inevitable that MPs will throw out the PM’s woeful plan on Tuesday, possibly by a majority of more than 100.

3 Theresa May must delay this week's vote on her Brexit deal Credit: AFP

That is not just defeat. It is catastrophic defeat.

The PM could immediately face a vote of no confidence triggered by power-hungry Labour.

The Parliamentary arithmetic means that she could narrowly lose this vote — even if she manages to win the support of every MP on the Conservative benches behind her.

It would raise the terrifying prospect of Corbyn and his rag-tag band of half-baked Marxists in Downing Street.

3 Jeremy Corbyn would reverse Britain's hard-earned economic and social progress Credit: Reuters

Not only will Corbyn fritter away the country’s hard-won economic and social progress but he will also pursue policies which are a disgraceful betrayal of Brexit and millions of his own voters.

In the face of the dismaying scenario before her, the PM has no choice but to postpone Tuesday’s crucial vote on her deal.

It will be difficult and humiliating.

But it will give her vital breathing space at Thursday’s EU summit to address the grievous concerns over her backstop proposal.

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Even the most blinkered of Brussels Eurocrats, whose intransigence so far has led to this crisis, must realise that such a concession is as much in their interests as ours.

Mrs May has often stressed her determination to act in the national interest.

Does she really think it is best for this country to press on with a vote which could hand victory to Jeremy Corbyn?