Lancashire County Council has fallen victim to a scam by bogus recruitment companies – costing taxpayers thousands of pounds.

The fraudsters, who pretended to have placed job adverts, collected more than £21,000 from the council before the fraud was spotted.

And County Hall’s trading standards chief admitted: “This is exactly the sort of thing we warn people about.”

The scam has been revealed in a report setting out the council’s anti-fraud measures and special investigations over the past year.

The bogus companies, which claimed to have placed job adverts in national newspapers, sent invoices to the council’s HR media team, which is in charge of processing bills. By the time auditors cottoned onto the scam, £21,336 had been paid.

Staff were warned about the tactics and invoices worth another £11,724 were stopped at the last minute.

Jim Potts, the county council’s chief trading standards officer, said: “We are not immune. Businesses, which include local authorities, are constantly being bombarded by scams. They send demands, which look exactly like real invoices, and hope they are paid by the payments department.”

The fraudsters addressed the “invoices” to the individual council officer named in other genuine adverts. This made staff believe the demands were genuine. Ruth Lowry, head of internal audit, described it as a “sophisticated scam”.

Details of the crime were passed to police, but the fraudsters have not been traced.