An estimated 75,000 private security guards will be operating illegally next week when new legislation comes into force, according to the government body responsible for regulating the industry.
From Monday it will be illegal to work as a security guard or CCTV monitor without a licence from the Security Industry Authority (SIA).
A last-minute rush for licences has left a massive backlog as checks with the Criminal Records Bureau take a standard two weeks to complete.
The SIA told the Times that only 45,000 security staff were expected to have licences by Monday, out of an estimated 120,000 workers.
Employers who take on unlicensed security staff could be jailed for up to five years, while the guards themselves face £5,000 fines and six months in jail.
“We are disappointed that some parts of the industry have been slow to take on a new regulation which is so important for the industry,” an SIA spokesman said.