GALE force winds and strong tides sank a rowing boat on the Thames in Barnes on Sunday.

Forty rowers were rescued after the weather caused chaos at the Vesta International Veterans' Head of the River Race, which runs from Putney to Mortlake.

Crashing waves overwhelmed many of the crews on the route. One boat split in half and five boats sank.

One 62-year-old rower was transferred to hospital for treatment for severe hypothermia, while 12 rowers were in a state of shock and distress and were warmed up in various rowing clubs.

The race organisers' safety boats were rapidly exhausted and the race safety officer asked for assistance from the RNLI base at Chiswick Pier, which already had two of its boats on the water in a back-up role.

Lifeboats were called to the event, in which 145 boats were taking part, at around 1pm after vessels took in water.

Safety co-ordination was taken over by Martin Blaker, the helmsman of the Chiswick Lifeboat, who oversaw the recovery of 40 people from the water.

David Clarke, of Chiswick Lifeboat, said: "Eights do sink regularly but when six sink at once, it's quite unusual.

"I think they were caught out by the weather - the river can be looking OK, and then you turn a corner and it can be crashing waves."

Asked if the weekend held bad omens for the 150th Oxford Cambridge boat race on Sunday, March 28, he said: "It's still a way off, we will be looking out for harsh weather conditions.

"We will have had the perfect warm-up if there are any problems."