Who can issue a CP12?

The short answer fits in a sentence: a Gas Safe registered engineer, and nobody else. The longer answer is about what registration actually covers, how to check it in thirty seconds, and why “can I just do the CP12 myself” keeps being asked and keeps being no.

Why is Gas Safe registration the law?

Because gas work done badly kills, so the law restricts who may do it. Anyone carrying out gas work in the UK must be on the Gas Safe Register, which replaced CORGI registration in 2009. Registration isn't a one-off badge: engineers hold specific competencies (for example domestic boilers, cookers, or commercial catering), and can only legally work on, and certify, the categories they're qualified for.

What does “qualified for the appliance type” mean?

Registration is by category of work, not a single pass. A domestic engineer holds the core qualification plus categories for the appliances they work on: boilers, cookers, fires, water heaters. Commercial work and LPG carry their own competencies again, so an engineer who's excellent on domestic natural gas boilers may not legally touch a commercial kitchen or a park home. The back of the ID card lists exactly what they can do, and that list is the boundary of what they can certify. Behind the categories sits ACS reassessment every five years, so the competence is re-proved rather than grandfathered.

How does an engineer earn those qualifications?

Through a route with no shortcuts. A recognised training programme, either a Managed Learning Programme or an NVQ, combined with a portfolio of real gas work carried out under the supervision of a registered engineer, then the ACS assessments: CCN1, the core domestic gas safety assessment, plus one for each appliance category the engineer intends to work on. Only then can they register with Gas Safe, and the proving doesn't stop there. Registration renews every year, and every ACS qualification is reassessed on a five-year cycle, so the engineer signing your CP12 has demonstrated their competence recently, not once in the distant past.

How do you check an engineer before they start?

Can a landlord, agent or handyman issue their own CP12?

No. The duty on the landlord is to have the check done by a registered engineer, and the record's authority comes from that engineer's registration and signature, not from the form. A landlord filling in a blank CP12, however carefully, has produced a document with no legal standing, and unregistered gas work is itself a criminal offence. The same goes for the plumber who's “basically gas trained” but not on the Register. If they're not registered, the record isn't valid and the work wasn't legal.

It cuts the other way too. If you suspect gas work has been done by someone unregistered, a suspiciously cheap “certificate” with no licence number, say, you can report it to the Gas Safe Register, which investigates illegal gas work. For a landlord, a record from an unregistered person is worse than no record at all: the duty is unmet, and the paperwork suggesting otherwise is part of the problem rather than the defence.

Who can issue the commercial equivalent?

The same principle with a higher bar. Non-domestic premises, shops, restaurants, offices and plant rooms among them, get their annual inspection recorded on a CP17, the Non-Domestic Gas Installation Safety Report, and it must come from a Gas Safe registered engineer holding the relevant commercial competencies, not just domestic ones. Commercial catering appliances carry their own categories again. A first-rate domestic engineer is simply not registered for commercial pipework or plant, and a report they signed wouldn't be valid, so businesses should check the ID card exactly the way landlords do.

What should the record they issue actually show?

The engineer's name, Gas Safe licence number and signature, the date of the check and the next-due date, the property and landlord details, and every appliance and flue checked, each with its result and any defects and action taken. The licence number is the thread that ties the paper to the Register, which is why a certificate without a traceable one isn't worth filing. It also settles a common misunderstanding about replacements: Gas Safe Register doesn't issue certificates and can't reissue yours. The record comes from the engineer or firm that did the check, and so do copies, which is why a lost certificate starts with a phone call to whoever carried it out.

Where does software fit in?

Software is the engineer's clerk, never their substitute. A tool like Manifold lets a registered engineer complete the CP12 on their phone at the property, reads the analyser and the data plate with the camera for the engineer to confirm, and produces the signed record in seconds. Every entry is still the engineer's judgement; what disappears is the evening of retyping. That division of labour is the honest version of a “digital CP12”, and it's the only version that produces valid records.