An unregistered gas fitter misled customers into believing he was a legally-registered gas engineer and then carried out work that put lives at risk.
Clive Farrant, 57, from Chelmsford, used a false Corgi registration number in adverts and paperwork when trading as Essex Plumbing Connection. He also committed offences as a director of Secret Heat Ltd. Both companies were registered to his home address.
The Health & Safety Executive (HSE) found Farrant had carried out gas work at several properties and left them all in a dangerous condition.
He worked at a number of homes in and around Chelmsford, Essex, between July 2006 and June 2009. During the same period, he also instructed another unregistered engineer to carry out work at properties in Tadley, Hampshire and Chelmsford.
It is a legal requirement for any gas engineering business or self-employed gas engineer carrying out domestic or commercial gas work to be registered under the Gas Safety (Installation & Use) Regulations 1998.
Farrant admitted 10 out of 11 charges relating to the Health and Safety at Work Act 1974 and Gas Safety Regulations 1998 when he appeared at Chelmsford Crown Court. He was fined £23,000 with £5,000 costs.
After the sentencing, HSE inspector Samantha Thomson said: "There is no excuse for illegally carrying out work on gas appliances – and to falsify documentation in order to defraud customers is not only a terrible thing to do but also a very serious offence.
"It is illegal for any unregistered person to carry out such work. When unqualified workers try to bypass the law in this way they are not only putting themselves at risk of prosecution, a large fine and a lengthy time in prison – they are also putting their customers' lives at risk."