What an opportunity the Tories have, in the next few days, to start the long climb back to office.

Oppositions usually have to wait for more than a year before they can begin serious combat with a newly elected government still glowing with victory and success. Not this time.

Labour is not exactly a shambles, but it has taken Sir Keir Starmer an amazingly short time to fall into a large muddy hole and then dig himself deeper into it.

Not only is he in trouble for accepting indefensible gifts, as are several members of his Cabinet, but his choice of Sue Gray as his Grand Vizier continues to cause him profound internal difficulties with others who resent her influence and doubt her supposed brilliance.

It also reminds many of her curious role during Boris Johnson‘s supposed ‘Partygate‘, an inflated non-event revisited by Mr Johnson in his enjoyable new memoirs in The Mail on Sunday and in our sister paper, the Daily Mail.

How can she have been the non-partisan servant of the state when she was soon to become the loyal Chief of Staff of the Labour leader?

This tangle will haunt Sir Keir and Ms Gray for years to come, and rightly so. But for the moment it may be overshadowed by the Budget difficulties of the new Chancellor, Rachel Reeves.

Encouraged by her stone-faced boss, she has for weeks been talking the country down and spreading gallons of gloom all around her. This having backfired, both with investors and the public, she now seeks to impersonate Little Miss Sunshine.

But there is not much sunshine to go round. Labour prevented itself from raising several major taxes by the promises it made in its own election campaign. Whatever can she do on October 30 that will not look feeble, hurt large sections of society or be a breach of an election pledge?

So the Tories are right to speed up their leadership election to ensure that their new boss is in place before Budget Day itself.

It is an unbeatable chance for them to make their mark, whoever it may be, and to show that the world’s oldest political party is back in business.

And that means the coming days in Birmingham, when the remaining four candidates face various sorts of grilling, will be even more intense than they would otherwise have been.

We hope that everyone involved will take full advantage of this. The choice of the final two candidates, which will follow, is the most important decision Tory MPs can currently make. Let us hope they make it with a due sense of just how much may hang upon it, setting aside trivial factionalism or crude ambition.

And after the turmoil of the post-Brexit Tory Party, the membership need to know in great detail who they are voting for and how they will perform.

The depleted ranks of the Parliamentary Conservative Party may look overwhelmed in a Commons dominated by Labour. But – as we already see – a big majority is not a guarantee of success, especially one with such shallow foundations in actual votes.

The Tory MPs who survived the debacle of July, or who have newly arrived, must surely have learnt the key lesson, that division and squabbling are never good, and always lead to failure.

The opposite rule also applies –that a serious, determined unity can pull them out of the swamp of defeat. So they should take great care to pick a leader who can inspire unity of purpose, and hit Labour where it hurts, from the Budget onwards.