When politicians break their promises, they generally try to downplay the matter. But delivering a set-piece speech atop an exposed construction platform in Kidbrooke Village, under a beating sun and several storeys above the ground, Sadiq Khan clearly wanted this U-turn to be made in the bright light of day.

For years, the mayor of London has promised to protect the capital’s green belt. Then, in his big speech last Friday, he announced that was set to change.

Launching a consultation which will lead to a draft for the next London Plan, Khan said that his office was going to “actively explore” development on select areas of the green belt.