Dozens of raids will be made on rogue security firms employed by pubs, clubs, and other properties in the next few months because only half of Scotland's guards and door stewards are licensed under new regulations.

The Herald can reveal that just 8700 of the 17,000 employees eligible have been licensed under legislation which takes effect today. From now, those without licences will not legally be allowed to work.

The legislation, which follows high-profile concerns about the involvement of organised crime in the industry, covers door stewards, security guards, cash-in-transit couriers, and CCTV contractors.

Those caught working without a licence can get a fine of up to £5000 or six months in prison. Firms supplying unlicensed workers face an unlimited fine and jail sentence of up to five years.

The police and Scottish Crime and Drugs Enforcement Agency (SCDEA) is co-operating closely with the Security Industry Authority (SIA) to close down rogue firms. Some 20 in the west of Scotland have already been warned they are at "high risk" of not being ready on time.

The legislation is already in force south of the border and, in the past year, officers and representatives from the SIA have carried out visits to 620 construction sites and executed 56 warrants. Fifty-one private security companies have been investigated and 138 people have been convicted of working without a licence.

Tom Porter, head of interventions at the SCDEA, said: "We know that organised crime is involved in a number of companies . We know these companies use intimidation, violence, and threats to obtain clients. We know that prior to the regulations coming in, certain companies have been looking at rebranding as a possible way of getting around the regulations."

An SIA spokeswoman said: "The estimate of those who need to be licensed under the regulations in Scotland is 17,000. 8700 licences have been granted."

David Dickinson, chief executive of the British Security Industry Association, said: "Businesses should ensure any contract security officer that works on its premises is suitably licensed."