Certificates · Guide · 4 min read

CP12 explained: the landlord gas safety record done properly

Manage landlord gas safety records, renewal dates and delivery of copies. A paperwork guide for qualified engineers and trade businesses.

By Trade PA · Published 29 September 2026 · Reviewed 15 September 2026

This is the second in our certificates series; the electrical equivalent is covered in What is an EICR?. Same idea, different fuel: a competent person inspects, records and signs, and a landlord relies on that signature.

What a CP12 actually is

Officially it is the Landlord Gas Safety Record. "CP12" is a leftover: CORGI Proforma 12, from the days when CORGI ran gas registration. Gas Safe Register took over in 2009, but the name stuck the way Hoover did, and the whole industry still says it. Whatever the header on your pad says, it is the annual record of the gas safety check that the Gas Safety (Installation and Use) Regulations require landlords to have.

Who needs one, and who can issue it

Landlords have duties for the gas appliances and flues they provide, and the check must be carried out by a Gas Safe registered engineer qualified for the relevant work. The exact duty depends on the property and arrangement; use HSE guidance for Great Britain and the relevant authority for Northern Ireland. This article covers managing the record, not how to conduct a gas safety check.

The landlord's side of the bargain: a copy to existing tenants within 28 days of the check, a copy to new tenants before they move in, and records kept for at least two years. Plenty of landlords do not know those rules. The engineers who quietly keep their landlords compliant are the ones who keep the work year after year.

The 10-to-12-month window

Since 2018 the renewal works like an MOT. Do the next check anywhere in the two months before the deadline, months ten to twelve, and the expiry keeps its original anniversary date: the landlord loses nothing by booking early. Do it more than two months early and the clock resets to the new date. Leave it past twelve months and the property is out of compliance until it is done.

The practical play is to book month eleven. It protects the anniversary, leaves slack for access problems, the eternal curse of tenanted work, and it turns your CP12 book into a predictable rolling round instead of a monthly scramble of expiries.

What you are actually checking

Leave the technical examination, testing and safety decisions to the appropriately registered engineer. A booking note or an app’s default tick is not a completed inspection. The record must reflect the work actually done, the findings and any action required.

And the distinction worth saying out loud to every landlord client: a safety check is not a service. One confirms the appliance is safe; the other keeps it that way. Selling both honestly, check plus service, is better for the appliance, the tenant and your day rate, but never let a landlord believe the CP12 alone means the boiler has been serviced.

What must be on the record

HSE lists the minimum record details: the checked appliances or flues and locations; engineer name, registration number and signature; check date; property address; landlord or agent details; defects and remedial action; and confirmation of the checks required by the regulations. Verify the full record against HSE’s list.

Where it goes wrong

Missed anniversaries, because the dates live in a diary nobody reads. Tenant copies never issued, which the landlord finds out about at the worst possible moment. Defects noted verbally and never recorded, which as far as the paperwork is concerned means they were never found. And records that exist as a photo on a phone that got upgraded. None of this is bad gas work; it is bad admin around good gas work, and it is the part that ends up in front of the HSE when something goes badly wrong.

The steadiest work in the trade

Look at what a CP12 round actually is: a recurring annual requirement for relevant properties, a legal deadline driving the booking, and a landlord who wants to hear from you before the date, not after. A list of landlord clients gives you a starting point for renewal conversations, plus the remedial work the checks surface. The engineers who lose that book are not the ones doing worse checks; they are the ones whose renewal dates lived in their head.

Keep renewal dates, contact details and copies of the issued record with the job. Trade PA can help organise the appointment and invoice, but the competent engineer must complete and validate the safety record. Check reminders and delivery explicitly; do not assume a recurring appointment or saved certificate has reached the tenant.

Build a renewal list someone else can understand

Use one row per property, not one row per landlord. Record the last check, the renewal deadline, booking status, access contact, issued record location and the date copies were sent. A landlord with six properties should not have one ambiguous “gas due” reminder.

Before closing the job, open the saved document, check its property address and confirm how the landlord will provide tenant copies. Keep access attempts and follow-up actions. Record “unable to gain access” honestly; it must never silently become “check completed”. Plan earlier appointments to allow time for access problems, without treating that planning buffer as an extension of the legal deadline.