Week by week the gulf between the Prime Minister and the Leader of the Opposition has widened until they seem like inhabitants of different planets, speaking different languages, unable to communicate or sympathise with each other, determined to treat each other as an alien and essentially despicable form of life.

Sir Keir Starmer inhabits Planet Fact. Each Wednesday he tries and fails to subject the Prime Minister to the laws of Planet Fact.

Boris Johnson inhabits Planet Freedom. Each Wednesday he declares his freedom to believe whatever he wants to believe, regardless of any pettifogging objections from the Leader of the Opposition.

Starmer began by observing that two-thirds of those with Covid-19 are not being reached by the track and trace system, and urged Johnson to agree “there’s a big problem”.

Johnson insisted that on the contrary, Starmer “has been stunned by the success” of track and trace.

Starmer proceeded to a more general condemnation of the Prime Minister for “brushing aside challenge, dashing forward, not estimating properly the risk”.

The Prime Minister responded to this attack on his whole way of life with an attack on the Leader of the Opposition’s way of life. He said Starmer had misled the House.

The Speaker, Sir Lindsay Hoyle, intervened to point out that “nobody misleads” the House.

Johnson instead accused Starmer of “inadvertently giving a false impression”, and indeed of “yo-yoing” between different positions.

Starmer said he was relying on the Government’s own slides, and added that the PM “should welcome challenge that could save lives”.

Will Starmer succeed in making Johnson look like a reckless joyrider who is leading us to our deaths?

Or will Johnson make Starmer look like a joyless pedant who is seeking to infect us with needless negativity?

Starmer summed up the case for the prosecution: “He’s been found out. He either dodges the question or he gives dodgy answers. No more witnesses. I rest my case.”

Johnson was unrepentant. One of the delights of Planet Freedom, he suggested, is that one can laugh to scorn the morbidly conscientious attitudes which prevail on Planet Fact.