Actually you can’t “go” here anymore.
This subterranean pissoir is no longer abluted by its passing clientele. These days, customers buy coffee and cakes, not drop the kids off by the pool. The toilet has been transformed into a cafe. It’s in Foley Street on a the corner of Great Titchfield Street. The metal frame that is above ground is of high quality and was made by Gomes Forge in Buckinghamshire, a company any still going strong today.
The coffee is good but I didn’t feel entirely comfortable, perched against the urinals.