Cold-calling “had surprisingly good results” during University for Industry pilots in the North-east last year. Twenty- two per cent of those telephoned “on spec” signed up for a free taster course, according to a report by the Institute for Public Policy Research.

Similar marketing techniques have since been adopted by other colleges. The report notes: “At least two providers in the North-east are now using cold-calling to recruit with great success.”

But the law, designed to avoid unwanted calls from people selling fitted kitchens and double glazing, will also wipe hundreds of thousands of people from colleges’ lists of potential students.

The new law means that anyone who does not want to receive unsolicited phone calls can put their names on a free register. Companies which contact a person on the register face fines of up to pound;5,000.

A spokesman for the Data Protection Registrar said that calling people and persuading them to take courses - even if no money changed hands -would probably fall within the legal definition of “communicating any advertising or marketing material”.

“It is generally accepted that marketing is not just simply trying to sell people goods and services - it is anything encouraging people to do something.”

The “opt out” register - the Telephone Preference Service - has existed as a voluntary code of practice for four years. But since becoming legally enforceable a month ago, registrations have leaped by 100,000 to 385,000.

UFI director of marketing David Croisdale Appleby played down suggestions that the register could undermine its recruitment strategy - the UFI aims to sign up one million people a year.

“The legislation has been quite a long time coming. It is something we anticipated and it has not come out of the blue.

“We have a broad range of marketing approaches and this doesn’t seriously affect that at all,” he said.

Harvey McGavin