Jeremy Corbyn thinks he will be prime minister by the end of the year.

Sir Vince Cable believes there is every chance that by the time we next reach for the Christmas decorations there could be a second Brexit referendum on the cards.

And both think Theresa May is on her last legs.

But this perception – not just among politicians but the media as well – that Mrs May is on borrowed time is quite possibly misplaced.

Yes, she has little authority within her party. Yes, she has been embarrassed at the ballot box. And yes, she has to rely on others to keep her afloat.

But here are some other incontrovertible truths about the prime minister: she is tenacious, dogged and resolute.

So far the circling predators – Michael Gove and Boris Johnson in her cabinet appear to be the most menacing in the short-term – have been kept at bay.

Since the moment she stood outside Downing Street and called that doomed election catastrophe, chaos and disaster have clung to her. But she has battled on.

Now, with parliament returning on Monday and the focus inevitably set to return to Brexit, Mrs May is starting the year with a confidence she has not had for some time.

Pushing the Brexit talks over the line last month meant Mrs May could enjoy the most relaxed period she has experienced for some months. Even the sacking of her close ally and friend Damian Green just before Christmas played out well in the press with many commentators saying how strong she had been.

So here is my bold prediction for 2018: Theresa May is going nowhere.

Of course, her position is supremely delicate but it has held this long and is strengthening by the day.

The increasing stability at Number 10 is not just down to the prime minister's steadfastness though. Behind the scenes there have been some vital changes as well.

Since losing his Croydon Central seat and coming on board the Downing Street team as chief of staff, Gavin Barwell has steadied the ship. Previously Mrs May had Nick Timothy and Fiona Hill jointly filling the role and the pair were divisive.

Undoubtedly hard-working and intelligent they could also be ferocious. That approach is all well and good when you are winning but if you need to call the favours in during times of strife you can suddenly find you've run out of friends.

Mr Barwell is well respected by his colleagues in the House of Commons and because he has been an elected member they have a kinship with him that was not there for the previous regime.

And there is another impressive figure that has grown in stature in Downing Street since the election, Sir Jeremy John Heywood the cabinet secretary. It is Sir Jeremy's job to deliver on the government's policy promises, so in many respects he gets the very final nod when plans are discussed at cabinet.

Previously Mr Timothy and Ms Hill kept their boss at a distance from the civil service, even Sir Jeremy had to make an appointment to see the PM. But not anymore.

These days Sir Jeremy is frequently by the side of the prime minister and for this the country should be grateful. He has served four prime ministers – Blair, Brown and Cameron before May – and his experience is vast.

During the tough days, weeks and months ahead as Britain attempts to plot a course through Brexit and beyond to a prosperous future Mrs May will need to surround herself with very serious, competent people. In Mr Barwell and especially Sir Jeremy she has perhaps finally found those people.

But of course there will be bumps in the road ahead for the prime minister and the slightest problem could result in the wheels falling off.

For now at least Mrs May is going nowhere. Could she even achieve the most extraordinary political turnaround in history and leave office with a favourable legacy? She will certainly give it all she has got.