What he doesn’t say is that the problem of discharges has been addressed and solved, without the mayor having anything to do with it. Neither he nor the media in general have bothered to celebrate the practical completion (in the same week as the Boat Race), of the Thames Tideway Tunnel. This is now being tested and will come into full action next year, eliminating 95 per cent of ‘incidents’ where heavy rain results in overloading of Joseph Bazalgette’s extraordinary Victorian sewerage system which served London so well for so long.

As usual, the extraordinary increase in London’s population over the last 30 years is ignored as a part-explanation for the increase in discharges. Two million extra inhabitants (the number is still rising fast) generates of lot of you-know-what.

Anyway, let’s celebrate the Thames Tideway Tunnel, the most significant piece of infrastructure for London since the Thames Water Ring Main, finished in 1997 though one should forget neither the Jubilee Line nor the Elizabeth Line in a set of great achievements which suggest our metropolis can still feel like a world-class city.

In the case of TT, the fact that it is largely invisible means that it lacks the glamour required for the sort of ritzy, photogenic celebration our mayor loves so much. For ideologues (he is partly one) who believe that private sector investment inevitably results in the public being ripped off, TT is an unhelpful example of private capital put to effective use for public benefit. Needless to say, this project was opposed on planning grounds by the usual collection of hopeless luvvies incapable of understanding the infrastructure needs of London in the 21st century.

Infrastructure underpins the life of all cities – it is surprising that given the extreme shortage of London housing that this subject is not being treated as though it were, but that would probably be too much to expect from politicians of all persuasions who believe the answer to shortage is to impose ever-more restrictive policies on the only people who are providing new homes at scale – housebuilders and housing associations.

All one can say is that there are cities with infrastructure problems which require even more urgent attention that London’s rivers. The latest example is Venice. We all thought that the multi-billion ‘Mose’ tidal barrier programme would put an end to ‘acqua alta’ disasters, and stabilise (literally and metaphorically) the city’s water problems.

Not so, it seems. Rising canal levels are having an insidious effect on the structures underpinning the city’s palazzos, in particular causing the rusting of tie rods which connect walls to floors. A report in The Times quotes Mario Pina, the architect responsible for the restoration of St Mark’s Basilica, as saying the structural issues can be addressed, but will require billions of Euros to be successful. This is not just about climate change; that hasn’t helped, but other contributory factors include the pumping out of ground-water over the past two centuries, causing clay to compact. In addition to rising water, the city is slowing sinking.

Cities are all about water, and its politics. Which brings us back to London. At least we have our Tideway Tunnel – but where are plans for the necessary additional Thames Barrier, to resist that supposedly one-in-500-years freak event that would cripple the capital? Unfortunately, we can’t rely on it happening in 500 years’ time. It could be tonight.