It is thought to be a consequence of increased health awareness, which means that more of us are seeking to relieve the strains of everyday life by turning to swimming.
"Swimming for health has created pressure for lane swimming and caused some conflict," said Ralph Riley, chief executive of the Institute of Sport and Recreation Management, which sets leisure industry standards and qualifications.
It is a point not lost on Maria Lonergan, duty manager at Finchley Lido in north London, where a lifeguard and a learner swimmer are considering legal action after an alleged attack involving a more competent swimmer. The dispute allegedly arose over whether the swimmer could be allowed an extra five minutes in the pool.
"I've been in poolside management for 12 years," said Miss Lonergan. "It has become more aggressive, and it's getting worse.
"People come here to relieve stress but someone cuts them up as happens when you're driving and they get more wound up."
Lifeguards at Finchley are instructed not to get involved in arguments between swimmers but to blow a whistle - the thinking being that, since the adults are behaving like children, they will respond to a playground-style command.
A lifeguard at another London pool said the fast lane was known in the trade as "the ego lane". "We get a scuffle every day in the fast lane," he said. "Some people get in the pool to take out their frustrations, as if they've bought the lane when they bought their ticket."
How you behave when swimming depends on what your goal is in the pool, says Andy Lane , sports psychologist at Brunel University. "If your goal is just to have a swim then you are less likely to get involved in confrontation. But if you have a target, there is a chance you will get frustrated. It depends on what other swimmers are doing whether you achieve that goal."
The problem appears to be that swimming puts people in an unnatural situation. "People feel self-conscious about their bodies or their swimming ability. You are taking part in a public performance but the goal is to swim on your own," said Mr Lane.
"If someone taps you on the feet, it as though they are saying: `Get out of the way, I'm better than you.' That's not nice and is an invasion of personal space."
Primitive species in the water
The Piranha: Vicious middle lane inhabitant. Irritated that not quick enough for fast lane and relieves frustrations by nipping heels and elbows of the unwary.
The Beluga Whale: Floats along languidly in middle lane, causing vast hold-ups and splashing water in all directions.
The Penguin: This unshapely creature waddles ungainly to pool side. In water, however, effortlessly - and infuriatingly - swims past all but the fastest.
The Leopard Seal: Most aggressive species, usually male. Hostile. Wears goggles, cap and nosepin. Will charge over or under those in his path.
The Jellyfish: The slowest water-borne species. Will simply float along, often walking with arms aloft wearing a slightly puzzled expression.
The Sea Horse: Congregate for conversation at the shallow end, forcing you to shorten your length or fight to the lane's end.