But the ban – last updated in 2003 – only applies to traditional television channels and not to streaming television delivered over the internet. With audiences increasingly switching off traditional broadcast channels, the UK’s big political parties are preparing to take advantage of the loophole and pay millions of pounds to insert themselves into living rooms.

Tom Edmonds, who ran digital advertising campaigns for the Conservatives in the 2010s, said politicians were desperate to pay to access screens. He said if British broadcasters did not run such ads, US tech companies would happily take the money. “You are going to see political ads on your TV. A lot of it will go on YouTube because you can get it in HD on your TV,” he added.

In the past, British political parties did not have enough money to buy campaign adverts. But Labour and the Conservatives are set to take advantage of a little-noticed rule change announced last year by Michael Gove, which will increase the amount national political parties can spend on a general election campaign from £19.5m in 2019 to £35m for the next general election.