The Garden Bridge continues to divide opinion, mainly over cost, but some things count for more than money

was first dreamt up in the wake of the London Olympics, when the beanc o unt e r s doi ng their c o s t - b e ne f i t analyses of public projects realised that there was something beyond calculation: the feelgood factor.

The second charge is the obverse of the public money argument: it is that the bridge is privately funded, so it is not really a public space. Around £90 million of private money and charitable funds have been pledged. The upside is that the Government only has to open its purse for a set amount and the people who will be left with egg on their faces if they don’t secure the final £30 million of private funding will be the trustees of the Garden Bridge.

Because there is public money in the mix, the Mayor, Sadiq Khan, clear-eyed and unencumbered by the projectitis that beset his predecessor, can tweak the proposal t o m e e t p e o p l e ’s objections. And he has — fewer than 12 closures for private events, a red line on TfL spending and more visits for local schools. And, unlike Boris’s downstream cable car, the Garden Bridge would actually be used.

Then there are the questions about whether using the design services of Thomas Heatherwick was some kind of favouritism. That’s for Khan, who is reviewing the procurement process for his appointment, to judge. Heatherwick, though, is not just the bloke who once did up Joanna Lumley’s friend’s house quite nicely so he was worth a punt. He is one of the finest designers of our generation, asked by Danny Boyle to design the Olympic cauldron, asked by Google to design its new Mountain View campus, and already designing a floating garden in the Hudson River outside New York. He is world class and was always going to be in contention.

What has been proposed is a new centre to London, one that places a little bit of the countryside right at the heart of it, which is itself the antithesis of most development — a place to do nothing. Given that much of the country resents the unnatural speed of London, they might be perversely pleased to see our next big project as a place in which we are all encouraged to slow down and admire the natural world.

As the imaginary Cabinet meeting rolls on, David Davis would inevitably growl: “What’s the point of it?” And someone brave might at this point say: “What is the point of nature?” Then Big Ben strikes the hour, and the Cabinet look at their watches. May might want to reflect on this: deep in the archives of the Houses of Parliament there is said to be a note about its reconstruction after the original burnt down in 1834. With a keen eye on public expenditure, a bean-counter queried why it should have two towers. The one over the House of Lords was fine but did the Commons really need one? Big Ben turned out to be quite a success.