The mayor has promised developers a discount on his Crossrail levy in new guidance today.
It says Boris Johnson is to allow developers to pay just 80% of his £20 per sq ft tax, for projects starting before 31 March next year, in order to encourage development.
But hang on. Almost every new scheme to stump up for the levy so far has had its payment negotiated down to just 20%, so in effect developers could see their contribution quadruple... hardly a great saving, or a great incentive.
By sheer coincidence, the only scheme to pay 80% of the levy, some £4m, is Commercial Estates Group's Columbus Tower in Canary Wharf, which by sheer, mind-blowing coincidence was the first and only scheme to have been approved by the mayor under his new powers to determine planning applications.
Not that there is any suggestion that the planning permission was sold for Crossrail money. Well, actually there is, from Labour's London Assembly Member John Biggs, who questions the mayor here, here and here. Oh, and here.
But Boris has denied any wrong-doing, insisting planning policy was followed and there is "no question of this application being bought".
Meanwhile, developers in 9-Elms, it was confirmed today, will be spared the levy altogether, but will pay a near-identical amount to London's other great infrastructure challenge, the extension of the Northern Line.
