A man received a ten‑month prison sentence, suspended for twelve months, after illegally replacing a boiler—an act that risked carbon‑monoxide leakage. The work took place in February 2023 at Balston Road, Parkstone, Poole, Dorset. David McCallum, 58, of McCallum Plumbing & Heating, was prosecuted when the installed flue was deemed “immediately dangerous”. He was ordered to pay £3,907 compensation and £7,064 costs by Bristol Magistrates’ Court on 13 February 2026.
The Gas Safety (Installation and Use) Regulations 1998 require anyone undertaking gas work to be registered with the Gas Safe Register and to hold the relevant qualifications. McCallum pleaded guilty to breaching Regulations 3(3), 27(1) and 27(5). He was also placed under a six‑month electronic monitoring order restricting his movements over weekends.
The homeowners noticed problems with the boiler shortly after installation and, concerned for safety, hired an independent gas engineer who deemed the work ‘immediately dangerous’. The incident was reported to HSE, leading to their investigation.
HSE’s investigation found that the boiler flue was not sealed or correctly positioned, creating an immediate risk of carbon monoxide entering the home. The work was carried out without any Gas Safe registration.
HSE inspector Simon Jones said:
“David McCallum undertook gas work which he knew he was not registered to do – and his shoddy work replacing the boiler and flue meant there is an immediate danger of carbon monoxide leaking into the property.
“McCallum’s illegal gas work put the lives of innocent homeowners at risk for his own financial gain.
“All gas work must be conducted by registered Gas Safe engineers to ensure the highest standards are met to prevent injury and loss of life. Installers will be prosecuted if they carry out gas work without the proper qualifications.
“I advise all householders to check that anyone they allow to work on the gas supply is gas safe registered. This can be done in just seconds.”
The prosecution was led by HSE enforcement lawyer Julian White, HSE advocate Rowena Goodwin and Paralegal Farhat Basir.
Members of the public can verify a gas engineer’s registration instantly via the Gas Safe Register website (www.gassaferegister.co.uk) or by calling 0800 408 5500.
Further information about this case, related legislation and guidance can be found on the HSE website, the UK legislation portal, and sentencing guidelines for health and safety offences.
illegal gas work — Key Findings
- David McCallum, 58 – owner of McCallum Plumbing & Heating
- February 2023 – illegal boiler relocation and flue installation at Balston Road, Parkstone, Poole
- Boiler flue not sealed or correctly positioned, creating carbon‑monoxide risk
- 10‑month prison sentence (suspended for 12 months) plus £3,907 compensation and £7,064 costs
- Bristol Magistrates’ Court – sentencing date 13 February 2026
- Breach of Gas Safety (Installation and Use) Regulations 1998 – §§ 3(3), 27(1), 27(5)
- Prosecution team: Julian White (enforcement lawyer), Rowena Goodwin (advocate), Farhat Basir (paralegal)
Why This Matters to Employers
Employers must ensure gas work is carried out by a Gas Safe registered engineer. Non‑compliance breaches the 1998 Regulations and can lead to imprisonment, fines and reputational damage.
How to Protect Your Business
- Conduct a thorough risk assessment before any gas‑related work to identify hazards and required controls.
- Brief your team with regular toolbox talks on gas safety, emphasizing the need for registered engineers.
- Review your policy templates to ensure they require Gas Safe registration for all contractors.
- Maintain a register of qualified gas engineers and verify their status on the official Gas Safe Register before work begins.
- Implement a post‑work verification step, including testing for carbon monoxide levels after any boiler or flue installation.
Frequently Asked Questions
What is an “immediately dangerous” gas hazard?
An immediately dangerous situation (IDS) occurs when a piece of equipment, such as an unsealed boiler flue, poses an imminent risk of serious injury or death – in this case, the possibility of carbon‑monoxide poisoning.
How can I check if a gas engineer is registered?
You can verify registration instantly by visiting the Gas Safe Register website or calling 0800 408 5500.
What penalties could my company face for illegal gas work?
Penalties can include suspended prison sentences, unlimited fines, compensation orders, costs, and electronic monitoring orders, as demonstrated in this case.