One problematic aspect of the regime of Covid controls which governed our lives for the better part of two years was the extremely uneven manner in which they were enforced.

The rules were often vague, and the legal authority underpinning them shaky. The police had a lot of discretion, which they exercised in different ways in different times and places. The result was scarcely equal justice.

Partygate has put the spotlight back on this. In some ways, it can be helpful to the Prime Minister, as when his allies can point to the injustice of Nicola Sturgeon and Mark Drakeford being let off with a slap on the wrist for their own apparent breaches of the rules.

More often, however, it risks a toxic contrast with ordinary members of the public who have been subject to eye-watering fines.

Yet with Boris Johnson having been issued his first fixed penalty notice (FPN), and the prospect of potentially several more in the pipeline, there is another problem: the police, at present, don’t have to publicly set out their reasoning for each decision.

In theory, of course, the Prime Minister could challenge the FPN in court, in which case presumably the Met would have to explain themselves. But there are sound enough political reasons for him to demur from such a course of action even if, as he claims, he personally disagrees with the police’s judgement on the event in question.

But that does mean that we potentially have the future of the Government hanging on a set of decisions of which the public will get no clear explanation.

Given that the current investigation into Downing Street is already the product of special circumstances – Cressida Dick waived the usual bar on retroactive investigations – it shouldn’t be difficult to tweak normal procedure and have officers explain why Johnson is in breach of the regulations on X occasion but not on Y occasion.

This is absolutely not to contest the legitimacy of the decision; it is absurd to suggest, as have Johnson’s allies to the press, that it is improper for the Met to conduct an investigation which might imperil the Government.

But whether or not there should be adequate transparency of how it was made is another matter. If there is a chance that issuing these FPNs ends up in a change of leadership, sunshine is the best policy.