partygate
The Labour leader said now is the time for "unity" in the UK against Vladimir Putin.
The Chancellor has joined the prime minister in being questioned under caution.
MPs close to the prime minister believe he will remain in post even if he is fined for breaking lockdown rules.
The prime minister completed a Metropolitan Police questionnaire over the partygate allegations.
But Europe minister James Cleverly indicated the PM would stay on even if he received a fixed penalty notice from the police.
Conservative MPs are split over whether to dump the PM or give him another chance.
The prime minister has until 10pm on Friday to return a questionnaire to detectives investigating the scandal.
"He thinks he is in an episode of Geordie Shore."
The prime minister is visiting Scotland but won't meet with Scottish Tories - or ordinary members of the public.
An ally of the PM said: “There is inevitably a degree of discretion here. Do you want the Met Police deciding who the prime minister is?"