In reply to Offwidth:
I work in a building right on the edge of Salford Quays and whenever it's hot, the water is teeming with people of all ages jumping in from the sides or off the bridge and generally swimming around and having run. After the unfortunate death of a 19 year old lad at the weekend there's been a police / PCSO presence all around, warning people of the dangers (I'm presuming they're telling people that swimming isn't allowed but being ignored as it's not having much effect).
Education and swimming safety has to be the way forward, surely. Telling kids not to swim in water seems like a bit of a pointless exercise especially when it's as hot as it is at the moment. Water is like a magnet to kids.
I've been a bit guilty in previous years of inwardly tutting at people swimming in the Quays when it's been hot. Then it suddenly dawned on me I was only doing it because I'm bitter and jealous at the fact I was watching them from a hot, stuffy office.
But yeah, stay safe. Get your kids familiar and comfortable and confident with water from as early an age as possible.