American swimmer Hill Taylor stunned the crowd at a university event by completing the 50m backstroke in an astonishing 23.1 seconds - almost a second faster than the world record.

But the University of Texas star was denied a place in the record books since he swam the entire race under water, breaching rules that limit backstroke contestants to swimming no more than the first 15m of the race beneath the surface.

The rule restriction is due to the fact that swimmers can move much more quickly under water. They can take advantage of the superior hydrodynamics of the so-called "streamline" position, in which they point both hands dead ahead, tuck their heads into their collarbone and kick both legs in unison.

Taylor was well aware of the regulation, but decided to show off his skills in any case for the sake of bragging rights - and also to the delight of the crowd.

Until the rules are changed, Britain's Liam Tancock will continue to hold the record with 24.04 seconds - but Taylor can at least console himself with becoming a global web sensation after a video of his sub-aqua swim hit the internet.