In a widely-trailed speech tonight, Sadiq Khan is to call for the government to devolve immigration policy to him in City Hall, as well as have an honest debate about rejoining the Single Market. At the Mansion House tonight, Sadiq will call for “Devolving powers to London and allowing us to create a regional shortage occupation list”. Implying shortages are being caused by lack of immigration when a record 504,000 people net came here last year seems to be a stretch even for Sadiq…

“Devolving powers to London and allowing us to create a regional shortage occupation list would be one way to give businesses the ability to attract and retain talent in the areas they need it most.”

Responding to the demand, a government source jokes to Guido, “What’s the mayor proposing? The Republic of Khania?” Going on to observe “I’m sure Londoners would prefer him to help sort out crime across the city rather than start worrying about setting his own immigration policies.”

Such a policy – provided Sadiq actually means it and isn’t merely cynically attempting to grab headlines – raises a number of questions about how it would be implemented. Would you need a passport to get on the tube? Would the migrants be fitted with ASBOs to ensure they stayed in London? Or would Sadiq merely demand the government build a wall around the M25? Enough time has passed since he delighted in attacking Donald Trump at the expense of Britain’s diplomatic interests – surely Don would pick up the phone should Sadiq need some advice…