An Oxford teacher plunged into a lake and saved the life of a construction worker after his digger fell into the water.

Rowing coach Michael Righton dived into Dorney Lake, in Slough, Berkshire, smashed the submerged digger's window and dragged unconscious contractor Eddie Randtoul o safety.

Mr Righton, sculling coach and head of science at The Dragon School, in Bardwell Road, was teaching a group of children when he saw the digger slide off the bank into the five-metre deep lake last Wednesday.

When the driver failed to reappear, Mr Righton called emergency services and leapt into the lake.

He said: "It was submerged with only the arm of the crane out of the water. The roof of the cab was level with the lake and completely filled with water.

"The window was closed and I tried to smash it, but couldn't. Then a worker threw me a hammer from the bank."

Mr Righton broke the glass and pulled out Mr Randtoul, 56, before giving him mouth-to-mouth resuscitation on the roof of the cab.

The Thames Valley and Chiltern air ambulance took Mr Randtoul to Wexham Park Hospital, in Slough. He was allowed home on Friday afternoon.