London is one of those cities that makes you work hard to discover some of its best features.
I'd lived here nine years before making my first visit to the Men's Pond at Hampstead Heath.
Synonymous with 'cruising' (for gay sex), Hampstead Heath is a vast green open space in North London. It takes a bit of planning to get to but is relatively accessible via public transport.
What's perhaps less well-known is that as well as being a hot-spot for outdoor sex, Hampstead Heath is also a major centre for outdoor swimming - options include: Parliament Hill Lido; the Mixed Pond; the Ladies' Pond; and the Men's Pond.
Large, freshwater swimming ponds, the Ladies' and the Men's ponds are unique in the UK as they are the only life-guarded open-water swimming facilities that are open to the public every day of the year.
The Hampstead Heath ponds are fed by springs of the River Fleet and were originally dug in the 17th and 18th centuries as reservoirs to meet London's growing demand for water.
The Men's Pond has an incredibly social atmosphere - on a warm summer day most of London's gays seem to converge on the grassy bank adjacent to the entrance to the pond. Groups of friends congregate, strip down to their speedos, share snacks and drinks, pose, promenade, people watch, and work on their tans.
Before entering the water you pass through a changing facility with showers, which also provides a secluded area for sunbathing - on the right clothing is required, on the left clothing is optional.
Once through the changing facility you enter the pond via a wooden jetty - you can slide discreetly into the water off the side of the jetty, but the preferred entrance is to dive in via the springboard, the more spectacular the dive the more appreciative the audience of onlooking swimmers.
In the late summer of 2012 swimmers in the Men's Pond were advised not to swim nude due to an increase in the number of Red Swamp Crayfish - a species native to North America but increasing in numbers in the Hampstead ponds, using their powerful claws to catch fish and defend their territory.
After a fairly long and miserable winter, I'm confident that this is the year that London has a long burst of unseasonably hot weather throughout the summer months.
If you're looking for me I'll be working on my tan at the Men's Pond, dodging the crayfish.