ORCA the golden retriever was hailed a wonder dog last night after saving its owner's life just like Lassie, the canine movie legend.

Cheryl Smith, 22, was trapped for two hours in a rain-swollen ditch after her 300lb motorised wheelchair veered from a road and plunged down a 20ft embankment.

She came to rest with the wheelchair on top of her, trapping her legs.

It was left to Orca, who had been running alongside, to save her life - remarkably finding a man who was jogging in a nearby field and attracting his attention.

Orca leapt up and down and ran in the direction of the accident before returning to jogger Peter Harrison, who finally realised the dog was trying to get him to follow.

Orca led him straight to disabled Cheryl.

"It frightens me to think what would have happened to me if Orca had not been there. I owe him everything," she said.

The drama unfolded when Cheryl, a York University chemistry student, was taking Orca for a walk along a dirt track near her home in Heslington, North Yorkshire, on Sunday afternoon.

Orca, who finished rescue training eight weeks ago so that he could help Cheryl in emergencies, immediately sprang into action to find help.

Cheryl, who was treated at York Hospital for mild hypothermia, said: 'He was amazing. He did exactly as he was trained to do.

"There was no way I could have got out of the ditch. It was getting late and I was very cold."

She added: "I thought Orca was unbelievable anyway, because he can obey 105 commands, unload the washing machine and press buttons at the pedestrian crossing. He can now add saving my life to the list."

Mr Harrison said: "Orca really persevered to attract my attention. It's lucky he found me because the weather was so bad. Orca is a very intelligent dog."