Computer Weekly has also learned that the threats are continuing despite claims by the Office of Fair Trading (OFT) that it has taken action to stop them.
It has further emerged that collectors armed with identification cards and receipt books are calling on businesses and requesting payment for data protection registration. Information commissioner Elizabeth France says businesses should notify the police and not make any payment.
The sharp practices take advantage of confusion and uncertainty in the IT and other industries over which businesses must register and which are exempt from the Data Protection Act.
Official-looking forms, headed "Final Notice", are being targeted at small and medium-sized businesses, giving the impression that companies have committed a criminal act by failing to register under the Data Protection Act 1998, for which they could be fined up to £5,000. The forms also give the impression - incorrectly - that they have been sent by the office of the information commissioner, and that directors must register immediately by sending £95.
The actual registration fee is £35 - and many of the businesses sent the forms are exempt from registration or have already registered.
But some IT directors and managers, even those who had already registered their businesses, may have felt pressured to send the £95 rather than spend time trying to correct what could have been an official mistake.
In May, the OFT issued a statement that "misleading business advertising for data protection notification services has been halted following OFT action in the High Court".
A High Court judge had issued an injunction against specific firms and individuals, but Computer Weekly has learned that the threatening letters continue to be sent. Some "Final Notice" forms have been sent out in the past month; and several local newspapers around the UK have recently published complaints from businesses that have been targeted.