Ben Proud set a British 50m Freestyle Record in 21.86 at the British Gas ASA South West Region Youth and Senior Championships.
Competing at his home pool of Plymouth Life Centre, the 19-year old lowered the previous marker set by Adam Brown at the 2013 British Gas Swimming Championships by 0.06 seconds.
Proud - who finished second behind Brown at this year's British Champs in Glasgow last month - now holds the British Records for both the 50m Freestyle and 50m Butterfly, which he set last year.
The teenager also becomes just the third British male swimmer in history to duck under the 22 second barrier for 50m Freestyle, joining Brown and five-time Olympian Mark Foster.