At least 13 elderly women have been fleeced of all their cash while travelling on buses by a smartly-dressed pickpocket.

The con, which involves dropping coins to create a diversion, has fooled three woman, all in their 60s and 70s in just one week, and 10 others over the last six months.

And police believe more thefts have gone unreported.

They are warning the elderly to hang on to their handbags if someone sitting next to them starts talking about money.

In the latest theft last Wednesday at 11.10am, a 72- year-old was on the 213 bus from Cheam to Kingston when a man wearing a suit and carrying a coat sat beside her.

He asked if some money on the floor was hers, but when she said no, he leaned across and stole her purse from her handbag.

She described the man as Asian, around 30, thin, 5ft 6ins with short black hair.

Although this description differs slightly from the other victims accounts, police are linking the muggings as the same trick is being employed.

In the second incident two days earlier, a 68-year-old was on the 151 bus at 3.30pm. Again, the man sat down next to her and said she had dropped some change. She said it wasnt hers and after passing her a blue bag, he stole £10 from her handbag.

On June 22 at around midday, a 69-year-old woman travelling on the number 80 from Morden to North Cheam had her bag containing £110 and her pension book snatched.

Police are working with the description of a mixed-race suspect, between 25 and 36, athletic with short black hair and a soft voice. He is usually smartly dressed wearing a grey suit, dark smart jacket or a dark raincoat. On one occasion he wore metal-rimmed glasses.

DCI Paul Conway said: If someone is sitting next to you and is talking about money then grab hold of your handbag. We are appealing for any information.

Call Detective Sergeant Janet Milligan on 020 8649 0731, or Crimestoppers, anonymously, on 0800 555 111.