Police are warning people across the Thames Valley to be on their guard against courier fraudsters posing as police officers.

The fraudsters are very sophisticated. One claimed to be a Superintendent from the Metropolitan police, telling his 80-year-victim on the phone that she had had money withdrawn from her account. He said the money had been returned but asked her to draw it out again so it could be checked in case it was counterfeit.

He arranged for the money to be collected and she has now lost that amount.

Police warn people not to fall for an old trick used by this man.

He told his victim to phone 999 to check he was genuine. But all a fraudster has to do is leave the line open and any number dialled will simply lead straight back to them.

Another Thames Valley resident received a phone call on Friday, April 20 telling them that they owed a large amount of unpaid tax from a previous year. They were warned that if it was not paid immediately a warrant would be executed for their arrest. The victim was so frightened she transferred money to the fraudsters' account.

Banks are now co-operating closely with police, looking out for signs that vulnerable people are being victimised.

Anyone doubting the legitimacy of a call is asked to disconnect their telephone at the wall, plug the phone back in and call 101.

For more advice about how to protect yourself against fraud and identity theft from Thames Valley Police please visit www.thamesvalley.police.uk/advice/protecting-yourself-and-others/fraud-and-identity-theft/