Landlord gas safety certificate in London: what the law asks

London has one of the largest private rented sectors in the country, and many lets in south and west London are flats in converted houses, each with its own combi. If you let a home with gas appliances, the law asks for a few clear things every year.

The core duties

The HSE guidance for landlords and letting agents is based on the Gas Safety (Installation and Use) Regulations 1998. In short, a landlord must:

Duty	What it means
Yearly safety check	Every gas appliance and flue you provide checked every 12 months
Gas Safe engineer	Done by a Gas Safe registered engineer
Copy to tenants	Existing tenants within 28 days of the check
Copy to new tenants	Before they move in
Keep records	At least two years
Maintain appliances	Keep appliances, pipework and flues in a safe condition

What a CP12 is

The record of the check is commonly called a CP12. That was the CORGI form number before the Gas Safe Register took over in 2009. The legal name is a landlord gas safety record. It lists each appliance, where it is, what was checked, and any defects found and action taken.

Which appliances are covered

The check covers gas appliances and flues you provide. That usually means:

• The boiler
• A gas hob or cooker you provide
• A gas fire you provide
• Flues serving those appliances

Appliances a tenant owns, such as their own gas cooker, are the tenant’s responsibility, though the flue serving them may still be yours. The engineer may flag anything unsafe they notice.

What happens at the check

A Gas Safe engineer checks each appliance for:

• Gas tightness
• Correct burner pressure or heat input
• Safe removal of fumes through the flue
• Adequate air supply where the appliance needs it
• Safety devices working

If anything is dangerous, the engineer follows the gas industry unsafe situations procedure. That can mean turning off the appliance, with permission, and labelling it.

Gas safety check vs service

The safety check is not a full service. It does not include taking the boiler apart and cleaning it. A service does. Landlords also have a duty to maintain appliances, and HSE says good practice is to show regular, annual maintenance. Most boiler makers ask for a yearly service. Our post on the gas safety check vs boiler service explains why many landlords book both.

Using a letting agent

Many south and west London landlords use letting agents who book the yearly check. Your management agreement should make clear who is responsible. HSE says the duty can pass to an agent under the contract, but you should still make sure the check is done and keep copies of the records.

If you self manage, keep a simple list of each property, the date of the last check, and when the next is due.

The two month window

Since 2018 you can have the check done up to two months before the due date while keeping the original expiry date. For example, if a record expires on 31 August, a check done any time from 1 July keeps a 31 August expiry the next year. Our post on early renewal shows how to use it.

Access

You have to take reasonable steps to get access for the check. Tenants should let the engineer in, but if they refuse, keep a record of each request. Our post on tenant access explains what HSE expects.

Carbon monoxide and electrical rules

Two other rules often go alongside gas safety:

• Carbon monoxide alarms. Since 1 October 2022, landlords in England must fit a CO alarm in any room used as living accommodation with a fixed combustion appliance, excluding gas cookers. See the gov.uk guidance.
• EICR. Private landlords in England must have the electrical installation inspected at least every five years. That is done by an electrician. Our post on EICR and gas safety certificates covers both.

Converted houses in Brixton and similar areas

In areas like Brixton, a single Victorian house may hold three or four flats, each with its own boiler and meter. Gas meters are often grouped in a front garden box or shared hall. If you own several flats in one building, book them on the same day so all the records share a date. Our Brixton area page covers the housing.

What happens if you do not comply

HSE investigates and prosecutes landlords who fail in their gas safety duties. In October 2026, HSE reported a landlord sentenced for leaving a gas boiler unchecked for eight years.

Booking a check

Give us the address, the number of gas appliances, and the tenant or agent contact. You can add a full boiler service to the same visit. See our landlord service and CP12 page.

Gas work in the UK must be done by a Gas Safe registered engineer. Check the engineer’s ID card and the number on the Gas Safe Register.