POLICE and consumer groups are warning North Yorkshire businesses to beware of a rise in bogus callers selling advertising.

Firms have received calls from salesmen claiming to be working on behalf of the police, fire service and local council.

Despite not agreeing to advertise in publications claimed to be safety leaflets and school books, several companies have been invoiced regardless.

Others have been invoiced more than double the quotation given on the phone.

Often there is no proof the advert has ever been published.

One firm was sold advertising in a book about child abuse and drug use from a firm claiming to be linked to the council. The price quoted on the phone was £58 - the invoice asked for £180.

In another case, the manager of a nail salon complained after being offered free advertising in an educational book she was told would be supplied to local schools.

The customer agreed on the basis that it was free, but later received an invoice for £202.

Government watchdog Consumer Direct said callers often targeted small businesses.

Staff say the nature of the cold call deliberately plays on the emotions.

John Field, contact centre manager for Consumer Direct Yorkshire and the Humber, said: "We urge firms to stay alert to this type of sales call.

"Make sure you know who you are doing business with, ask for their client list or references from businesses they have previously dealt with.

And demand to see examples of the type of material they have distributed."

This advice was echoed by Tony Lidgate, spokesman for North Yorkshire Police.

He said: "This warning from Consumer Direct is very timely as yet again there have been cases reported to us of salesmen who at the very least give the strong impression of selling advertising on behalf of the police.

"The most common complaint we receive is that a caller strongly suggests that if you don't place an advert you're not supporting your local police.

"No police force would touch this kind of approach with a barge pole and we would urge businesses not to even consider approaches of this sort."