The lapping of warm water...the giggle of childish laughter...the squelch of sun lotion and splash! - a sweltering city-dweller cools off in his favourite summer oasis, the lido!
To the strains of 'Lido Shuffle', Stephen Smith is dipping his toe in the waters of this great national institution, alas now in jeopardy.
On a morning swim, comedian Arthur Smith confides, "These will be the early ones - the ones who actually have swum two miles before they've even had a croissant". "Unthinkable", Arthur laughs.
Lidos were dreamt up in the 30s as a poor man's Riviera: the rich were going to the South of France for the summer, but on a good day at the Lido, you could almost believe that you were on the Croisette at Cannes rather than Tooting Bec; that it was caviar in your hand rather than a bloater paste sandwich.
In their heyday, thousands would turn out for the entertainment there....the early beauty contests brought people in their droves. Design guru and lido lizard, Stephen Bayley, says this country had never seen anything like it. "We regard them with fastidious distaste nowadays but they must have been unbelievably exciting in 1957".
John Ling - now in his 70s - remembers it well. He grew up in Ipswich near the Broomhill lido. "The air was electric", he tells Steve. He was a lifeguard at the lido, dated at the lido, and when he got married bought a house just opposite the lido!
The pools were nearly killed off by the advent of the package holiday in the 1960s and 70s, which meant that ordinary people could finally go to the real Med for themselves; suddenly, the lido looked very homespun and even naff. But many have survived and have a devoted following.
Former Labour spin doctor, Alastair Campbell, is one of those devotees. He confesses he found time to go to his local lido in Parliament Hill during his number 10 days....and that he made phone calls from the pool.
"Who to?" Steve asks. "If I told you I'd have to kill you!" Campbell teases.
We hear of the routine of a lido....the man who will only put his clothes in one cubicle - the no 10. He's been doing it for years. "I don't know how it happened...it's an even number thing", he laughs.
"I'm slightly obsessive compulsive about stroke counting" says another.
It's all in the life of a lido - Producer: Adele Armstrong.
Stephen Smith dips his toe in the waters of this great national institution.