Could Gavin Williamson be the next Prime Minister?

This time last week it would have still seemed an unlikely call.

But following his shock appointment as Defence Secretary, Mr Williamson has shot up the pecking order of potential successors to Theresa May.

While a few days ago you could have named your price on Mr Williamson landing the top job, he is now he is as short as 16/1 with some bookies.

And on close examination the idea of him one day being handed the keys to Number 10 is less outlandish than it at first appears.

One of the main factors in his favour is that the Tories are irrevocably divided, not just over Brexit, but also over the shade of blue the party wears in the post-Brexit years.

It is anyone's guess whether the party continues the leftward lurch that Theresa May has presided over, or returns to a more traditional form of conservatism.

The fact that there is no outstanding candidate to succeed Mrs May could play into Mr Williamson's hands.

She clearly sees him as the best among the new talent in the party, and a successful stint at the Ministry of Defence may broaden his appeal among MPs.

There is no doubt he has work to do on that front.

His appointment as Defence Secretary has been met with scathing criticism from a noisy but largely nameless few among the Tory ranks.

He has faced accusations that he is unsuited to the role due to his lack of experience. Others suggest that as Chief Whip he was in prime position to oust Michael Fallon and promote himself in one fell swoop.

It seems a bit rich to condemn him for allegedly playing a part in his predecessor's downfall, considering Mr Fallon has admitted that his behaviour in office had 'fallen short' of expected standards.

Part of the furore undoubtedly centres around the fact that Mr Williamson does not come from a traditional Tory background, having studied at a comprehensive school and Bradford University.

It is a point not lost on Paul Uppal, the former Conservative MP for Wolverhampton South West.

He said that Mr Williamson had 'broken the mould' of London-centric politics, but said it was too early to tout him as a potential Prime Minister.

"You would probably find there would not be this outcry if he was the MP for somewhere in Surrey," he said.

"Gavin has demonstrated that he is a very capable individual.

"You do not get to be a Secretary of State by chance, and it is clear that his talents have been recognised by the people around him.

"For the moment his sole focus will be on getting control of his new brief. After that who knows what could happen?

"For the time being it is just nice to see a West Midlands MP at the top table."

Mr Williamson's friend and predecessor in the South Staffordshire seat, Lord Cormack, advised him to 'take it one step at a time' and concentrate on excelling in his new position.

"I wish him every possible success," he said. "It is a crucially important job and I hope he can achieve as much success in this job as he did as Chief Whip.

"I admire what he has achieved up to now and who knows what the future holds.

"Let's see him as a successful Defence Secretary first. He needs to have some years in this very important job.

"Defence is the biggest responsibility of any government and Gavin has an enormous workload to contend with."

Henry Carver, a former chairman of the Wolverhampton Conservative Party, said Mr Williamson's new role could be 'the beginning or the end' of any desire for the highest office.

"The big test of any politician is when you get to run a major department," he said. "It will make or break him.

"History tells us there have been plenty of very capable looking people who have been hopeless in the top jobs, and others who did not appear to be as good that have done very well.

"Gavin has been excellent as a Chief Whip, but the Defence Secretary job is a massive challenge compared to dealing with 40 or 50 of the awkward squad.

"How he gets on will tell us whether or not he has reached the limit of what he can do."

History stands against Mr Williamson.

Edward Heath was the last Chief Whip to land the top job when he became Prime Minister in 1970.

However, his path to the top saw him hold several other ministerial and shadow cabinet positions before entering Number 10.

With Theresa May's zest for power seemingly waning by the day, such a swift step up may come too soon for Mr Williamson.

But strong handling of the devilishly difficult defence brief will put him in prime position for a future leadership bid.