The PM did not lie to the House of Commons. Now, ordinarily what goes on inside the House of Commons is not for lawyers like me to adjudicate. The 1688 Bill of Rights says ‘Freedome of Speech and Debates or Proceedings in Parlyament ought not to be impeached or questioned in any Court’. So normally I would stay silent.

But we are facing a very interesting constitutional crisis. Because whether someone lies is really a legal question. It has a test as law. A lie is defined in the dictionary as a factual statement that is untrue and made with intent to deceive. In the leading case of R v Lucas [1981] Q.B. 720 the courts found a lie must be ‘deliberate’. The PM could not possibly have lied by telling the house that he believed the Covid laws were followed – not unless he deliberately knew the law was against him. There is no way he fulfils the legal test – because no one knows today if the law is actually against him.

So why is the law uncertain? Lord Sumption a highly distinguished lawyer and former Supreme Court Judge, told the World at One on Radio 4 that he doubted what happened would count as illegal. I have argued that there is a defence available in law relating to events on Crown property. It is fair to say that noted lawyer Adam Wagner and the Metropolitan Police disagree with us. It’s equally fair to say Durham Police, in refusing to investigate Starmer when he was pictured drinking a beer in lockdown, agree with us that no law was broken.

So when the PM addressed the house, he can’t have been lying. At most he was confused on the law. He is not a lawyer. I am, but I have not changed my legal opinion. Should Crown immunity fail (and I would want it tested as an argument in a proper court before I gave up on it), then the second legal hurdle is whether the events were ‘reasonably necessary for work purposes’.

Law must apply consistently and must use those words. Those words ‘reasonably necessary’ are permissive. In 2022 all sorts of activities are reasonably necessary for work. To be restrictive, the law needed to have used words such as ‘absolutely essential for work purposes’ – or greater still ‘absolutely essential for core work purposes only’. But it didn’t. It only ever used ‘reasonably necessary’.

What is reasonably necessary for work in 2022 seems to me to be a very low bar. I do not believe Mr Starmer’s beers and takeaway were caught by this low legal test any more than I believe the appearance of a cake changed anything at No. 10. The idea that a cake arrives, or a bag of crips is opened and suddenly everyone in a room must immediately reverse and go home is not, I think, credible.

If you think I am wrong and take the restrictive view, then how do you account for people smiling at work? Going for fag breaks? Prayer breaks? What about pausing to film a TikTok video of nurses dancing? If your colleague Barry starts to tell you a joke, do you call the police? Do we think all were suddenly illegal? I think not and I would like, as a lawyer, to see what courts and appeal courts might say.

After all, there was a ludicrous private prosecution of the PM and that got even further than this level. That got past an actual judge (before more senior judges reversed it).

So the point is that there is still little legal certainty on new and expansive legislation such as the Covid laws – especially not from a police administered fixed penalty notice. Without legal certainty, there can never have been any lie. Parliament cannot make windows into the PM’s soul – if he says he believed the law wasn’t broken, there is no lie. Errors, mistakes, are not deliberate acts intended to deceive – if there even is an error.

But if legal certainty comes later, by a court ruling, then it doesn’t apply retrospectively. All cases are lost by someone and it is not customary to have the losing barrister subsequently accused of ‘lying’. We have courts and appeal courts for a reason.

What is interesting is how the law is, in our constitution, subservient to politics. Parliament can vote for an investigation into whether or not there was a lie. It can even say there was one – the law and courts can’t stop them. If it wants to parliament can pass a law saying water flows uphill. As a lawyer, I’d be forced to go along – but you would all be free to express a political opinion on whether the rivers had all reversed direction or not.

Politics matters. In our constitution, it matters more than law. It’s why we all vote and only some of us spend our time in courts. If parliament votes for a legal or factual absurdity then I will simply raise an eyebrow. You may very well look to your ballot.