I think we can draw some encouragement from the knowledge that there will always be people who will find their own way to get past the concrete and get back to the river, even if it doesn’t involve skinny-dipping at Putney. As an out-of-towner, my leisure visits to the capital tend to be focused around obvious areas, and sure enough last month, on one of the rare sunny days we had this summer, my wife and I were to be found wandering along the South Bank, and for the first time really noticed the tidal nature of the Thames. I’d never knowingly seen it at low tide before, but what really caught my attention was the sprinkling of people who’d descended onto the grey strip of sand to sun-bathe and enjoy the weather. This was a side of London that was new to me - London-on-Sea. And part of its beauty was that it was temporary. No one could build here; no one could take control of the beach away from the river and its tides. And it speaks well of the power of people to respond to an opportunity, spontaneously importing into their lunch hours and shopping trips behaviour from one location (be that Brighton or Ibiza) into another in order to create pleasure for themselves.

I'm looking forward to reading Ackroyd's Thames book. I suggest that it probably ought to be read in parallel with its nasty doppelgänger Iain Sinclair's Downriver. Sinclair's Thames is of course not sacred but is rather bubbling with all manner of filth; it is a flowing, shifting site of madness and mishap. Nobody enters this Thames for fear of contamination; and Sinclair's antiheroes, in a rustbucket boat drifting violently towards Sheerness, are lost souls. I think we have a complex relationship with our rivers and canals. We tend to regard them as dirty because of the legacy and the very present filthy practices of our waterside chemical and waste disposal industries. That's what Sinclair draws on in his very contemporary water-terror imagery. But in contrast, the denizens of London cleanse themselves with Thames water every day, make their Frappuchinos with it, water their garden plants and hanging baskets with it... and, if monied, choose to live in ex-industrial apartments alongside it ... That's where it's 'sacred' to them; no longer at the river bank; but processed, one-step-distant, and in private.