The swimmer got into difficulty yesterday and his rescue was spotted by a passing tour boat.
He was pulled into the lifeboat in shorts and shoes.
The RNLI is wearing of the dangers of wild swimming in the Thames because of cold water shock and hidden items.
It says “the Thames can be just as dangerous as the sea. Strong currents, submerged debris and bitterly cold water can trigger cold-water shock within seconds, leaving even strong swimmers caught out and unable to stay afloat.”
