A fraudster cruelly conned a 94-year-old woman after selling her a box of fish.
Halton Council has warned people throughout Cheshire and surrounding areas to be vigilant for this scam.
The conman knocked on the woman's door in Runcorn and offered her the box of fish for £20. She paid with a debit card and he took £270 off instead.
The same fraudster has been operating in Warrington and other parts of Cheshire over recent weeks so it is likely many more people have been caught out.
Trading Standards Officers are advising that if you have bought fish from a cold-caller please:
Check your bank statement to see how much has been debited from your account
Speak to your bank to ask for a charge back and consider cancelling your card
Let Trading Standards know via the Citizens Advice Consumer Helpline on 03454 04 05 06
Avoid being caught out by other doorstep rogues by refusing to deal with people who cold-call you.
You can get a free 'No Cold Calling' card and letterbox sticker from any Halton Direct Link.
Halton Borough Council's Executive Board Member for Trading Standards, Cllr Dave Cargill, said:
"This is particularly callous, due to the resident's age.