A major search and rescue operation got under way in Dorset yesterday after several swimmers at a British Heart Foundation sponsored swim went home after the event without telling organisers they had finished.

The story comes just a week after the RNLI was criticised for going ahead with a fundraising swim off the Kent coast near Margate at which a number of swimmers had to be plucked from rough seas by the RNLI’s own lifeboats.

In yesterday’s debacle, three RNLI lifeboats and the Portland coastguard helicopter were scrambled soon after 2pm when around nine swimmers were reported missing after the 1.4-mile swim between Bournemouth and Boscombe piers.

Conditions on the water were rough with blustery 25mph south-westerly winds.

Rescuers spent two hours searching a five-square-mile area of Poole Bay for the missing swimmers before discovering that they had simply gone home.

BHF event organiser Andy Coles admitted that the problem was caused by participants failing to notify the organisers that they had finished, and that check-in procedures would be reviewed in the wake of the fiasco.

More than 1,000 people usually take part in the annual swim, one of the biggest events of its kind in the UK.