I begin by making the best case I can for both Boris Johnson and Keir Starmer about the breaking of lockdown rules during the pandemic.

For the Prime Minister, that he didn’t believe that he was breaking any rules, that he didn’t mislead the Commons over what Sue Gray’s interim report called “social gatherings”, and that it is unfair for the Metropolitan Police to issue fixed penalty notices retrospectively – especially when they aren’t doing so elsewhere, and the Durham Police may be taking a different approach to Keir Starmer.

The case for the Leader of the Opposition is more narrowly focused.  It is that the Indian food and drink consumed by him, Angela Rayner, Labour staff and activists in April last year was done during a work break and not at a social event , so the rules weren’t broken at all.  Furthermore, it’s unfair for the occasion to be investigated retrospectively – especially since Johnson has a special responsibility for the rules, because the Government devised them.

It’s fair to say that the take of a voter who isn’t engaged in politics is most likely to be: a plague on both your houses.  Is there any reason to give Starmer’s conduct more attention other than Johnson’s, other than that it is in the interest of the centre-right Fleet Street papers to do so?

And if there is no intrinsic difference, why were broadcasters pressing Starmer about Beergate, as the Durham incident is now nicknamed, so hard during the run-up to the local elections?  After all, the BBC and Sky News are scarcely part of the “Tory press”?

The answer is that Johnson is partied-out, so to speak, at least for the moment.  He has been fined, and may be fined again.  And he is under investigation on two further fronts: from Gray over the social gatherings, and from the Privileges Committee over whether or not he lied to the Commons.

The media and his opponents will be back for more in the event of more fines, and after Gray’s report is published, but for a moment there is a pause.

Starmer’s behaviour, meanwhile, is news – since the Durham police have now announced that the incident last April will be investigated.  But there is another element that’s giving the story legs, as we journalists like to say.

It runs as follows.  One of the main accusations hurled at Johnson by his opponents is that he has no regard at all for propriety.  And that he constantly shows contempt for it – all the way from being sacked by the Times as a journalist for inventing a quote through that EU referendum bus to his threat to break international law over the Northern Ireland Protocol to Partygate.

Whatever you think of this narrative, it’s fair to say that Johnson is a Disraeli, so to speak, rather than a Gladstone, in terms of one of the archetypes of British politics.  That’s to say, he doesn’t tend to climb into moral pulpits and preach sermons (which in his case is just as well). He avoids claims to virtue.

Starmer is not exactly a moralist either, but he has got himself into a tricky position over Partygate.  “Honesty and decency matter,” he tweeted in January. “After months of denials the Prime Minister is now under criminal investigations for breaking his own lockdown laws. He needs to do the decent thing and resign.”

So were he to hold himself to the standard he applied to Johnson, he would already have quit.  But it is not as though his were a solitary tweet.  It was part of a wider campaign.  Starmer has been pressing his opponent as he might have done a suspect in court during his days at the bar.

For just as there is always a smack of the columnist about Johnson, whose priority is to entertain his readers, so there is that of the lawyer about Starmer – putting in the hours, mastering the paperwork, and doggedly pursuing his brief.

However, there is a bit more to it in this case, or so at least it seems to me.  The antagonism between Johnson and Starmer is real rather than staged, more so in my view than between many former holders of their posts.

Perhaps their backgrounds as well as their characters provide an explanation.  To Johnson, Starmer must seem a pettifogging nitpicker – a petty man compared to the Odyessean hero he conceives of himself as being.

And when Starmer pursues Johnson in the Commons, it is impossible to resist the sense that he believes the Prime Minister’s collar should be felt, and that he should be sent down without the option of a fine – to use the language of the P.G.Wodehouse story in which Oliver “Sippy” Sipperley is sentenced for 30 days for pinching a policeman’s helmet on Boat Race Night.

At any rate, the Mail on Sunday reports today that the meal was a pre-planned takeaway, not a spontaneous send-out for food.  The diary grid on which the event is detailed shows that Starmer’s team was due to arrive at their hotel at 18.30, walk to a miner’s hall at 20.40 for “dinner” and return to the hotel at 22.00.

There is nothing in it about work at all, let alone after the late hour of 22.00.  Much may turn on whether that plan was adhered to, whether the Labour team could reasonably have eaten earlier in the hotel or outside at other locations, whether masks were worn and social distancing observed, and whether those present were really working at all.

“For nothing is secret, that shall not be made manifest; neither any thing hid, that shall not be known and come abroad” – if the witnesses quoted in the Mail come forward, at any rate, and can prove that those present were “just getting p****d. They were just there for a jolly,”  as one of them puts it in the paper today.

What is driving my media colleagues even more nuts than usual are Labour’s institutional evasions: first, the denials that Angela Rayner wasn’t there at all; later, not coming clean about the planning of the event in advance.

History has yet to tell what Starmer was tucking into on that April evening, but there is nothing more that the panthers of journalism love feasting on than hypocrisy, and they are smacking their lips.

If Starmer gets a fixed penalty notice, he will find it hard to hang on.  What if he doesn’t?  I put a case to you – as the Labour leader himself might say.  Suppose he said today: “I don’t think that I did anything wrong.  But we’ve been less than candid with our friends in the media.  And Caesar’s wife must be above suspicion.  For that reason, I’m standing down as Labour’s leader.”

Such a sacrifice would be quixotic, possibly fruitless (since there’s no evidence that any potential successor would lead Labour more effectively) and leave a moral and political mare’s nest for his replacement.  Though it would have the side-effect of making Rayner’s position impossible, which he might regard as a plus.

It could have the same effect on Johnson’s.  Perhaps instead the Prime Minister would come to be seen as a survivor – the man who saw Starmer off, just as he previously saw off Jeremy Corbyn.  But perhaps instead more fines, the Gray report, and a bigger Labour lead would come together, triggering that elusive leadership ballot in the autumn.

If Starmer really wants Johnson out of Downing Street as badly as it seems, might the surest way of achieving his goal be to resign himself?