Muggers believed to be aged just 13 ripped a necklace from a pensioner's throat in a terrifying robbery, police have said.

The 67-year-old woman was waiting for a bus in Lampton Road, Hounslow, on Friday May 15, between 9am and 9.30am, when three hooded assailants are said to have approached.

One allegedly told her he had a knife and then demanded her money. He started to pull her handbag while the other two tugged the gold necklace she was wearing.

After taking the necklace, they ran off towards the A4 Great West Road, where they turned west towards Heathrow.

The suspects are described as being aged around 13. They were wearing dark waterproof-type jackets with the hoods up, and dark trousers.

Police, who are appealing for witnesses, said the victim had been left shaken and upset, with red marks on her neck and pain in her right shoulder.

No one has been arrested in connection with the alleged robbery.

Anyone with information is asked to call Detective Constable Craig Boosey on 020 8247 6650, or Crimestoppers, free and anonymously, on 0800 555 111.