The family spent the weekend searching for Oscar and putting up posters in the village asking anyone who has seen the little eight-year-old black-and-white Shih Tzu to get in touch.

William's mum, Theresa McGrath, of 1 Rolfe Crescent, said a local man contacted them on Sunday night saying he had seen a car almost run over a small black-and- white dog in a street near their home.

A young woman with two children in the car got out and asked the man who the dog belonged to. But as he did not know, she picked up the pet, put it in her car and drove off, Mrs McGrath said.

"We have informed the police, council, dog warden and the kennels. We have two very upset little boys, aged four and seven, wanting their dog back.

"William said it had ruined his birthday and seven-year-old Oliver didn't want to go to school today because he was so upset. They are worried that the lady with the children wants to keep him and won't give him back to them."

Oscar escaped between 10.30am and 11am as Tesco was delivering food for William's birthday party to the family home. Mrs McGrath said the dog had a blue collar with an identification barrel – but the paper with its ID details had been found in his bed.

Anyone with information about Oscar's whereabouts can contact the McGraths on 01485 570767.