The warning comes after Leeds Crown Court sentenced three men to prison on 8 June for their involvement in bogus data protection agencies.
Bogus letters were sent to thousands of businesses demanding registration fees of £135 to register under the DPA in a mail scam which could have netted up to £2m.
Neil Clark, prosecuting for the Crown, explained to the court that the fraudsters had already banked £62,575, and that thousands of printed bogus forms were ready to be posted to unsuspecting companies.
Liaquat Khan, 33, of Leeds, admitted two charges of conspiracy to defraud and was jailed for two and a half years.
Parminder Kaur Johal, 31, and Zahir Abbas Shah, 33, both from Bradford, also admitted two charges of conspiracy to defraud and were jailed for 13 and eight months respectively.
A fourth person, Nosheen Sheridan, 27, from Bradford, admitted one charge of conspiracy and was given an 18-month supervision order with 50 hours' unpaid work.
Judge Roger Ibbotson said that the fraudsters were involved in a substantial and systematic operation which specifically targeted the owners of small businesses and relied on their wish to act lawfully and not commit any breach of the regulations.
Detective Sergeant Lester Lee, from West Yorkshire Police, added: "The sentences passed today show that the courts take this kind of crime seriously.
"Anyone thinking of getting involved in such an offence should take note that we painstakingly investigate these crimes until we are able to put the offenders before the courts."
Simon Entwisle, chief operating officer at the Information Commissioner's Office, confirmed that if a business receives a letter out of the blue demanding more than £35 to register under the DPA it will be a scam.
"Our simple message to businesses is to disregard the letter and not to pay the fee demanded," he said.
The convictions follow a successful multi-agency operation involving West Yorkshire Police, West Yorkshire Trading Standards, the Health and Safety Executive and staff at the Information Commissioner's Office.
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