If Boris Johnson becomes prime minister today, he will face battles from the moment he enters Downing Street

Chancellor Philip Hammond - who has been a prickly thorn in Johnson’s side ever since the former Mayor of London confirmed his decision to become a contestant for the Tory Party leadership - has announced, to nobody’s great surprise, that he will resign from his post if Johnson wins, saying he cannot work alongside someone who’d be content with a no-deal Brexit.

But that does not mean Johnson will be free from Hammond’s strictures. Hammond can be as dangerous, even more dangerous, as a rebellious backbencher as he is a recalcitrant Chancellor.

Indeed, Hammond has already made clear that he is quite prepared to ditch Johnson if he does not get his way.

There are other pro Remainers in influential positions in the Conservative Party with whom Johnson will have to deal - and these are the sort of people who do not easily give up.

Johnson, however, appears to have forgiven the current Environment Secretary Michael Gove, who some months ago appeared to try to shaft Johnson. Gove could therefore find himself promoted in a Johnson regime. Whether Johnson will decide to keep on his leadership rival Jeremy Hunt as Foreign Secretary remains to be seen.

But the first few weeks of a Johnson administration will certainly be a bumpy ride, and he will have plenty of critics in the Conservative Party at Westminster with whom he will have to deal.

So we can look forward to a wholesale change of personnel in the Cabinet once the new regime gets underway.

It will be a far more robust affair than that of Theresa May, whose relatively short period as Prime Minister was bedevilled by Brexit.

That topic made it impossible for her to demonstrate her full skills as a Government leader and she had no help - indeed, she suffered from much disloyalty - from some of her Cabinet colleagues during her term of office.

However, people will look back on her premiership in years to come in a much better light than it is seen now. She deserved better of the people she led.

• The former Tory leader Iain Duncan Smith has been one of Boris Johnson’s principal backers during the leadership contest, and so he is likely to be offered a big job under the new administration.

Duncan Smith has come out hot and strong about the hijacking by Iran of the British oil tanker, saying that the Conservative Government should have put more precautions to stop this kind of piracy. He has been a total opponent of the EU Remainers, and thus is pretty well assured of a big job coming his way.

This incident has affected the leadership campaign of Foreign Secretary Jeremy Hunt, who, however, has never looked during the campaign like a winner. So it is pretty well assured that he will have to settle for second-best.

The arrival of Johnson is unlikely certainly in the first few months to alleviate the shambles in the Conservative Party, but so long as he takes a firm grip on those who disagree with him then he might inspire some sense of loyalty into the party.

• The Labour Party also has its problems, with Jeremy Corbyn coming under almost ceaseless attack.

The latest has come from Labour peers, who, some fear, are prepared to move a vote of no confidence in the Labour leader.

Even in the Commons, there is a groundswell of anti-Corbyn feeling among some Labour MPs - but Corbyn is proving difficult to destabilise.

He has already survived easily two attempts to dump him from the leadership, and he has proved popular among sections of the electorate.

He seems totally unfazed by these attacks on his leadership and shows no sign of giving in to his critics.

• It is not only the Conservatives who will be changing their leadership this week but also the Liberal Democrats, where Sir Ed Davey and Jo Swinson are battling it out for leadership of their party.

But it will take more than such a change to restore the Liberal Democrats as a party of any consequence at Westminster. They are easily outrun by the Scottish Nationalists and everyone else, and attempts by the current leader Sir Vince Cable to restore them to some kind of powerful or semi-powerful political force have crumbled by the wayside.

The Liberal Democrats’ future seems just as bleak now as it was at the time of the last General Election.