Schools are increasingly being targeted by organised crime groups, councillors have been told – with one Hertfordshire school subject to a "bizarre" fraud that included the offer of a piano.

The trend – or 'change in battlefield' – was reported to a meeting of the county council's audit committee, as part of a progress report on the work of the Shared Anti-Fraud Service (SAFS).

Data presented to councillors showed that between April and June this year 17 allegations of 'schools fraud' were made to SAFS.

And head of SAFS Nick Jennings recounted the "bizarre" fraud involving the offer of a piano.

He told councillors the school had been told that the piano was part of an inheritance – and that they could have it on condition that they paid for its delivery.

The fraudster, he said, then tried to encourage the school to make the payment.

But, he said, the fraudster was in Nigeria and the piano didn't exist.

Mr Jennings says the service tries to educate schools on the steps they should take if they receive unsolicited correspondence or correspondence from organisations that they don't know.

And he pointed to the need to take "great care" in responding to organisations not normally dealt with – or if receiving a "strange email" from an organisation that is normally dealt with.

Referring to a 'change in battlefield', he said that when new trends emerged they were shared with those organisations that might be affected by them.

According to data presented to the committee, there were 89 allegations of fraud reported to SAFS between April and June, in total.

The majority of those allegations (56) related to the use of blue badges, which help people with disabilities or health conditions park closer to their destination.

And councillors heard that blue badge theft was a "rising issue", particularly around the north of London – where they were told blue badges were being stolen from parked vehicles.

"They have a street value – particularly in London – because you can avoid the ULEZ and congestion charges if displaying a blue badge in your car," said Mr Jennings.

"So criminals are very keen to get their hands on blue badges."

Mr Jennings said they had run a campaign advising blue badge users to only display them when needed – and not to leave then in the car when the car wasn't in use.

In addition to giving the advice to legitimate blue badge holders, he said the operation had also looked at the misuse of the badges in car parks.

Working alongside civil enforcement officers he said they had inspected 76 badges – and seized six that were being misused.