What a CP12 Actually Is
CP12 is a trade shorthand for a Gas Safety Certificate issued to a landlord following an annual inspection of gas appliances, flues, and pipework at a rented property. The name comes from the old CORGI Proforma 12, which was the paperwork format used before Gas Safe Register replaced CORGI in April 2009. The form number is long gone but the name has stuck, and most engineers, landlords, and letting agents still use it as a catch-all term for the whole annual gas inspection process.
Strictly speaking, a CP12 is the document an engineer produces after carrying out checks required under the Gas Safety (Installation and Use) Regulations 1998. It records the results of inspecting each gas appliance, checking for flue integrity, verifying ventilation, testing for gas soundness, and assessing whether each appliance is safe to use. If something fails, the engineer records it, and the appliance is either made safe on the spot or disconnected. The document itself is then what gets handed to the landlord and, in turn, to the tenant.
In everyday usage, when a landlord says 'I need a CP12 done', they mean they need the annual inspection carried out and the certificate produced. When an engineer says 'I've issued the CP12', they mean they have completed the inspection and handed over the signed document. Both uses are broadly correct in practice, which is part of why the confusion with the phrase 'landlord gas safety record' persists.
What the Landlord Gas Safety Record Is
The landlord gas safety record is the specific term used in the Gas Safety (Installation and Use) Regulations 1998. Regulation 36 sets out the landlord's legal duties, and it refers to a 'record' rather than a 'certificate'. This is not a pedantic distinction. The record is a legal document with a defined minimum content, and it is the landlord's duty to obtain it and keep it, not simply the engineer's duty to produce it.
Regulation 36(3) requires that the record must include: a description of and the location of each appliance or flue checked, the name and address of the landlord or their agent, the address of the premises, the date of the inspection, any defects identified, any remedial action taken, a declaration by the engineer that the checks have been carried out, and the engineer's Gas Safe Register number. If any of those fields are missing, the record is not compliant, regardless of whether the job was done competently.
Regulation 36(6) requires the landlord to give a copy of the current record to each existing tenant within 28 days of the inspection being completed. For new tenants, the copy must be provided before they move in. Landlords who fail to do this are committing a criminal offence under the Health and Safety at Work etc. Act 1974, which underpins the Gas Safety Regulations. The Health and Safety Executive can prosecute, and landlords have been fined and given custodial sentences for persistent failures, so this is not a formality.
Key Differences: CP12 vs Landlord Gas Safety Record
The core distinction is this: CP12 is the informal industry term for the inspection and certificate, while 'landlord gas safety record' is the statutory term used in the Regulations. In practice, a properly completed CP12 document that contains all the fields required by Regulation 36(3) is the landlord gas safety record. The problem arises when engineers or landlords treat the CP12 as just a receipt for work done rather than as a legal document with mandatory content.
Understanding the differences below matters because a landlord cannot rely on an incomplete document to demonstrate compliance, and an engineer who produces a non-compliant record may face questions about their professional competence and Gas Safe registration.
- •Name: 'CP12' is informal trade terminology; 'landlord gas safety record' is the statutory term in Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998.
- •Origin: CP12 derives from the old CORGI Proforma 12; the landlord gas safety record has been a legal requirement since the 1998 Regulations came into force.
- •Who produces it: The Gas Safe registered engineer produces the document; the landlord is the person legally obliged to obtain, retain, and serve it on tenants.
- •Mandatory content: A CP12 template may or may not include all Regulation 36(3) fields; the landlord gas safety record by definition must include all of them.
- •Retention: The landlord must keep the record for two years from the date of inspection under Regulation 36(5).
- •Tenant service: The landlord must provide a copy to each tenant within 28 days under Regulation 36(6); the engineer has no statutory duty to send it directly to tenants.
- •Penalties: Failure to hold a valid record or serve it on tenants is a criminal offence under the 1998 Regulations, not just a contractual dispute.
- •Frequency: Both refer to the same annual inspection cycle; there is no separate 'landlord gas safety record inspection' distinct from the CP12 visit.
When Each Term Applies: Practical UK Scenarios
If you are a Gas Safe registered engineer quoting a landlord for annual gas safety work, the job is colloquially called a 'CP12'. On your invoice, on your job sheet, and in conversation with the landlord, that terminology is fine and universally understood. When you complete the inspection and fill in the paperwork, what you are producing is the landlord gas safety record in the eyes of the law. Your document needs to meet Regulation 36(3) regardless of what you call it.
If a letting agent is chasing paperwork from a landlord, they will usually ask for 'the CP12'. What they actually need to see is the landlord gas safety record. If the document the engineer has produced is missing the Gas Safe Register number, the engineer's declaration, or a list of the specific appliances checked, the agent should not be accepting it as compliant, even if the engineer has signed it.
If a landlord is audited by the Health and Safety Executive following a gas incident, the HSE will ask to see the landlord gas safety record, not a 'CP12'. They will check it against Regulation 36(3) line by line. A document that is informally completed and missing mandatory fields will not satisfy the inspector, and the landlord may face prosecution even if the gas work itself was carried out safely.
The Legal Framework: Regulation 36 in Detail
The Gas Safety (Installation and Use) Regulations 1998 are the primary legislation governing landlord gas safety duties in the UK. Regulation 36 is the specific provision that creates the annual inspection duty and the requirement to produce and retain a record. The Regulations apply to any landlord who lets a property with a gas installation, including private landlords, housing associations, and local authorities.
Regulation 36(1) requires a landlord to ensure that a Gas Safe registered engineer carries out an annual safety check on each gas appliance and flue provided for use by the tenant. There is a 12-month window: the check must be carried out no more than 12 months after the previous one, or within 12 months of a new appliance being installed. If the landlord lets the certificate lapse, even by a day, they are technically non-compliant from that point.
Regulation 36(3) sets out the mandatory content of the record, which is detailed in the previous section. Regulation 36(5) requires the landlord to keep the record for at least two years. Regulation 36(6) deals with tenant notification. Breaches of these Regulations are prosecuted under the Health and Safety at Work etc. Act 1974. The maximum penalty in a magistrates' court is an unlimited fine; in a Crown Court, the penalty can include imprisonment. HSE enforcement data shows landlords have received custodial sentences for repeated failures, so these are real consequences, not theoretical ones.
It is also worth noting that from a Gas Safe perspective, the engineer carrying out the work is obliged to be competent in the appliances they are inspecting. Gas Safe Register holds records of which appliances each registered engineer is assessed for, and an engineer who inspects an appliance outside their competence assessment could face suspension or removal from the register.
Common Points of Confusion Cleared Up
The most common confusion is believing that a signed CP12 is automatically a compliant landlord gas safety record. It is not, unless all the Regulation 36(3) fields are present. Engineers sometimes use older templates that do not include a Gas Safe Register number field separately, or that group appliance details in a way that makes it unclear which appliance failed which check. If the tenant or the HSE cannot read the record and understand what was checked and what the outcome was, it is not compliant.
A second common confusion is around who is responsible for chasing the annual renewal. The Regulations place the duty on the landlord, not the engineer. Some landlords assume their engineer will automatically remind them and book the next inspection. In practice, many engineers do send reminders, but if the landlord ignores them and the certificate lapses, the engineer is not the one committing the offence. Landlords who rely entirely on their engineer's diary rather than their own renewal tracking are taking a legal risk.
A third confusion is about whether the landlord gas safety record covers a gas boiler installed in a communal area or a meter cupboard. Regulation 36 applies to any gas appliance or flue provided by the landlord for the tenant's use. A boiler in a communal plant room that serves a tenant's flat is within scope. A gas fire that belongs to the tenant (not the landlord) is outside scope for the landlord's record, though the engineer inspecting may still flag visible safety concerns.
Finally, some landlords and agents believe that a new boiler installation resets the CP12 requirement. It does not. A new boiler installation requires a Building Regulations notification via a Gas Safe registered engineer (the engineer typically handles this as a competent person self-certification scheme), but this is separate from the Regulation 36 annual safety check. Both obligations exist independently.
Worked Scenario: One Job, Two Documents, One Legal Obligation
Here is a concrete example of how this plays out on a real job. Barry is a Gas Safe registered sole-trader engineer working in Leeds. He has a regular client, a private landlord called Mr Patel, who owns a terraced house in Headingley let to two tenants. The tenancy started on 1 March 2024. Barry carried out the first annual safety check on 15 February 2025, inspecting the combination boiler in the kitchen and the gas fire in the living room. He charged Mr Patel £85 for the visit.
Barry completed his CP12 paperwork on-site. He recorded both appliances, noted that the gas fire had a cracked fireback and was classified as 'immediately dangerous', disconnected it with Mr Patel's knowledge, and marked it as requiring replacement before use. He signed the document, included his Gas Safe Register number, and emailed a PDF to Mr Patel the same day. Total time from arrival to email: about 90 minutes.
Mr Patel now has the landlord gas safety record. His obligations under Regulation 36 are: keep the record for two years (until at least 15 February 2027), provide a copy to each of the two tenants within 28 days of the inspection date (so by 15 March 2025), and arrange the next annual inspection no later than 15 February 2026. Mr Patel also needs to arrange replacement of the gas fire before the tenants use it, though that is covered by his general duty to maintain appliances in safe condition rather than by Regulation 36 specifically.
If Mr Patel fails to give the tenants a copy by 15 March 2025, he is in breach of Regulation 36(6) regardless of the fact that Barry's record is perfectly completed. Barry's job is done. Mr Patel's obligation to serve the document is his own legal duty. This is the distinction in practice: the engineer produces the record, the landlord is legally responsible for what happens to it next.
What an Engineer's CP12 Document Must Include
When you are the engineer completing the inspection, your paperwork needs to capture everything Regulation 36(3) requires. Using a template that has all the fields pre-built reduces the risk of accidentally missing something on a busy day. Below is the minimum content your landlord gas safety record must contain for it to be legally valid.
Missing any of these fields means the landlord cannot demonstrate compliance, and if the HSE investigates, a poorly completed record reflects on the quality of your work regardless of whether the inspection itself was thorough.
- •Description and location of each appliance and flue checked (not just 'boiler' but 'Worcester Bosch 30i combination boiler, kitchen, ground floor').
- •Name and address of the landlord or their managing agent.
- •Address of the premises inspected.
- •Date of the inspection.
- •Any defects identified, including whether the appliance is 'At Risk', 'Immediately Dangerous', or 'No Defects Found'.
- •Any remedial action taken during the visit (e.g. appliance disconnected, advised not to use).
- •Declaration signed by the engineer confirming the checks were carried out.
- •The engineer's Gas Safe Register ID number.
Record Retention, Tenant Service, and What Happens When It Goes Wrong
Regulation 36(5) requires landlords to keep each completed record for two years from the date of inspection. In practice, most landlords with multiple properties use a folder system or digital storage. If a landlord cannot produce the current and the previous year's record on request, they are unable to demonstrate continuous compliance, which weakens their position significantly in any HSE investigation.
Regulation 36(6) requires the landlord to give a copy to each existing tenant within 28 days of the inspection. For new tenants, a copy must be given before they move in. This applies even if the tenant does not ask for it. The landlord cannot argue that the tenant 'didn't want it' or 'never asked'. The duty is absolute. A landlord with three tenants in a house in multiple occupation needs to give a copy to all three, not just the lead tenant named on the agreement.
When things go wrong, the consequences are serious. In 2021 the HSE prosecuted a landlord in Greater Manchester who had not carried out a valid gas safety check for over three years across multiple properties. The landlord received a fine of £12,000 and a suspended custodial sentence. Cases like this are not exceptional. The HSE publishes enforcement notices and prosecutions on its website, and the majority of gas-related landlord prosecutions involve failures around the record rather than the gas work itself. The engineer carried out the job; the landlord failed to manage the paperwork.
Gas Tightness Testing and the IGEM/UP/1B Edition 4 Update
If your CP12 inspection involves carrying out a gas tightness test on the installation pipework as part of your checks, be aware of a significant technical change coming into effect on 1 October 2026. IGEM/UP/1B Edition 4, which governs tightness testing and purging procedures for domestic and small commercial gas installations, changes how permissible pressure drop is determined during a gas tightness test.
Under Edition 4, the permissible pressure drop is no longer calculated by reference to the meter size. Instead, it is determined by the Installation Volume of the pipework being tested. Any perceptible movement on a gauge during a tightness test is no longer attributable to the installation pipework in the way the previous edition allowed. This has practical implications for how you conduct and document tightness tests on larger domestic installations where pipework volume is significant.
This change does not alter the Regulation 36 obligations themselves, but it does affect the technical standard you are working to when you carry out the inspection. Engineers who are used to applying the old pressure-drop table based on meter capacity will need to update their method. From 1 October 2026, any tightness test recorded on a landlord gas safety record should be carried out in accordance with IGEM/UP/1B Edition 4 methodology. If you are completing CP12 work regularly, it is worth reviewing the Edition 4 guidance before that date.
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