The Department for Education and Skills is advising schools not to buy licences for the service if they have purchased products from companies other than London-based Bromcom Computers. It is the sister company to Frontline Technologies Ltd, which holds a patent for wireless transmission of pupil data. FTL licences cost up to pound;1,500 a year, but the DfES believes its patent is not valid for other companies’ products.

However, a DfES spokesman was unable to say if it plans to challenge the patent, or would support schools facing a legal challenge. The department’s lawyers are still examining a recent out-of-court settlement of a licensing dispute between FTL and TASC Software Solutions, from Wolverhampton.

Ali Guryel, FTL’s managing director, insists it is entitled to protect its intellectual property. He said he would take legal advice if a school began transmitting without a licence - but hoped it would not come to that. “If it wasn’t for the DfES’s advice, schools would just get on with it - they buy licences every day. It is not appropriate for a Government department to act in this way.”