An elderly gentleman in Aylesbury paid £400 to a "Nottingham Knocker", doorstep callers who sell household products at inflated prices.

The scam is believed to originate in Nottingham and involves ex-convicts who claim they are part of a rehabilitation scheme.

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The conmen look for vulnerable victims they can scam and police say streets being targeted by the "Nottingham Knockers" often see an increase in distraction burglaries.

Thames Valley Police have a supply of "NO COLD CALLING" stickers for residents to stick on their door.

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A spokesman said: "The best way to avoid this happening to you is not to answer the door if you don't know the person.

"Any door-to-door sellers should have a genuine pedlar's certificate as well."