“The Labour Party is under new management,” Sir Keir Starmer declared. He got his message across rather well at PMQs.

In this endeavour, he had a certain amount of help from Boris Johnson, who was intent on attacking the old Labour Party, which was led by Jeremy Corbyn and parroted the Kremlin line.

The party has changed, Starmer retorted, and in any case, he himself never took orders from Corbyn about giving in to Moscow.

Tony Blair used to persuade middle England that he must be sound, by saying things which produced cries of anguish from the Left of the Labour Party.

Starmer is doing something similar: the more he renounces Corbyn, and is denounced by him, the sounder he expects to appear to normal, patriotic voters.

Johnson today tried to avert any impression that Starmer was sound by accusing the Leader of the Opposition of yielding to “pressure from the Islington Remainers who have seized on” the Russia report in an attempt to suggest that Vladimir Putin is “somehow responsible for Brexit”.

The Prime Minister used to live in Islington, where he was not taken seriously until he led Leave to victory in the EU Referendum, whereupon his neighbours paid him the compliment of starting to hate him.

So Johnson knows about the Islington Remainers and sees advantage in getting Starmer regarded as a paid-up member of that group.

Yet the Prime Minister also wishes to persuade us that Starmer keeps changing his views from week to week, even from day to day: “The Leader of the Opposition has more flip flops than Bournemouth beach.”

The Islington Remainers are reluctant to change their minds about anything, so Johnson may in the end have to decide which of these two lines of attack he proposes to maintain.

Starmer, annoyed to be thought inconstant, struck back at Johnson as “the former columnist who wrote two versions of every article”, a reference to the two articles Johnson wrote, for and against EU membership, as he wondered which side to back in the EU Referendum.

As Parliament breaks up for the summer recess, neither contender has established a clear ascendancy over the other. Each is  good at what he does, which is so different to what the other man does that there are times when they look like inhabitants of different planets.