Thieves preying on pensioners in the run-up to Christmas are watching them withdraw money inside banks and then distracting them with noxious substances outside so they can rob them.

Surrey Police are hunting two Asian women who are believed to be involved in stings in Dorking and Espom which netted them £1,000 on each occasion - but police believe there may be other victims who have not yet come forward.

Surrey Police have released CCTV images of one supect taken in Dorking on December 3 at the time of the first incident.

A woman in her 70s had visited Barclays on Dorking High Street to withdraw £1,000.

After leaving the bank, she walked with a friend across Sainsbury's car park when she noticed a strong smell and a yellow substance on the back of her jacket.

Shortly after, two women appeared, acting in an animated fashion - which the police believe was a distraction technique.

When she arrived home, the victim noticed the envelope containing her money was missing.

The next day, December 4, a man in his 90s withdrew £1,000 from the Epsom branch of Barclays at 11.30am.

After leaving the bank, the man sat down for a rest on a seat in The Ashley Centre when he was approached by two women who appeared to want to help him clean a noxious brown substance which had appeared on the back of his head.

It was later discovered that his money had also been stolen.

A Surrey Police spokesman said it is believed the victims were watched inside the bank by someone who then tipped off an accomplice outside.

Detective Constable Errol Chetty, investigating officer, said: "Preying on vulnerable members of society is an inexcusable offence and several teams are working together to identify those responsible for the offences.

"One of the lines of enquiry we have been following up is studying CCTV in both towns where the offences occurred.

"We are now able to release an image of a woman who was in Dorking around the time of the first offence and we believe she may hold information vital to this investigation.

"I would urge the woman or anyone who can identify her to contact Surrey Police with information.

"Sometimes, for whatever reason, people wish to provide information anonymously and this can be done through the independent charity Crimestoppers on 0800 555 111.

"I believe there could be other potential victims of these offences who have not yet come forward and I would ask these people to speak with us as we need to gather as much information on these crimes as possible."

The women involved in the Dorking theft were both dressed in dark clothes.

One was in her early 50s, about 5ft 1ins, stocky and wore glasses and a black fur trimmed hat.

The other was about 30-years-old, about 5ft 3ins and slim.

Contact Surrey Police with information by calling 101 and quoting reference 45140102501.