If you rent out a property in London, arranging a gas safety inspection every year is not optional. It is a legal requirement under the Gas Safety (Installation and Use) Regulations 1998, and failure to comply carries serious consequences for landlords, including fines, prosecution, and the loss of the right to serve a Section 21 notice to regain possession of the property.
Despite how long this legislation has been in place, there is still a surprising amount of confusion among landlords about exactly what the certificate covers, how often it needs to be renewed, and what their responsibilities are toward tenants. This guide sets out the answers clearly so that landlords across West London know where they stand.
What Is a CP12 Gas Safety Certificate?
The CP12 is the document issued to a landlord following a successful gas safety inspection carried out by a Gas Safe registered engineer. It records the date of the inspection, the address of the property, the engineer’s Gas Safe registration number, and the results of the checks carried out on each gas appliance and fitting in the property.
The inspection itself covers every gas appliance the landlord is responsible for providing, which typically includes the boiler, gas hob, gas fire, and any other fixed gas appliances. The engineer checks that each appliance is operating safely, that flues and ventilation are adequate, that there are no unsafe gas pressures or flow rates, and that there is no evidence of unsafe installation or deterioration.
It is worth being clear about what the CP12 does not cover. It is a safety inspection, not a service. A gas safety check confirms that the appliances are safe to use. It does not involve cleaning, adjusting, or maintaining the boiler in the way that an annual boiler service does. Landlords who want their boiler to perform well and last longer should arrange a separate annual service in addition to the safety inspection, though the two can often be carried out at the same visit by the same engineer.
How Often Does a Landlord Need One?
A CP12 must be renewed every twelve months. There is no flexibility on this. The expiry date is printed on the certificate itself, and it is the landlord’s responsibility to ensure a new inspection is booked before that date passes.
The twelve-month clock starts from the date of the inspection, not the date the tenancy began or the date the certificate was issued. If an inspection takes place in February 2026, the next one must be completed before February 2027, regardless of whether the tenants change in the interim.
For new tenancies, the landlord must provide a copy of a valid gas safety certificate to the tenants before they move in. For existing tenancies, the certificate must be provided within 28 days of the inspection being completed. Landlords must also keep a record of each certificate for at least two years.
What Happens if You Do Not Have One?
The consequences of failing to hold a valid gas safety certificate are significant and worth understanding clearly.
Gas Safe Register and the Health and Safety Executive have powers to investigate landlords who are not compliant. An unlicensed or expired certificate can result in a fine of up to £6,000 per appliance. In cases where a gas incident occurs at a property without a valid certificate, the landlord can face criminal prosecution. Courts have handed down custodial sentences in serious cases.
Beyond the regulatory consequences, there is the impact on tenancy management to consider. A landlord who does not hold a valid gas safety certificate cannot serve a Section 21 notice to end an assured shorthold tenancy. Even if the certificate lapses by a single day between the inspection and being served to the tenant, that notice can be challenged and invalidated. This is a very common and costly mistake.
From an insurance perspective, many landlord policies include conditions around gas safety compliance. A claim arising from a gas incident at a property without a valid certificate could be refused entirely.
How Quickly Can a Certificate Be Arranged in London?
For landlords who are approaching a renewal date or who have recently taken on a new property, the process of arranging a CP12 in West London is straightforward. West London Plumbing carries out gas safety inspections across all W and TW postcodes, with Gas Safe registered engineers available for prompt appointments.
An inspection typically takes between 30 and 60 minutes depending on the number of appliances in the property. The certificate is issued following the inspection once the engineer has confirmed that all appliances meet the required safety standards. Where a fault or unsafe condition is identified during the inspection, the engineer will advise on what remedial work is needed before a certificate can be issued.
What If an Appliance Fails the Inspection?
If an appliance is found to be unsafe during the gas safety check, the engineer is required to take the appliance out of use and advise the landlord on the necessary repairs or replacement. A certificate cannot be issued until the issue has been resolved and a follow-up check confirms the appliance is now safe.
This is not a situation landlords need to fear, but it does underline the importance of not leaving the inspection until the last possible moment. Booking with enough lead time means that if a fault is identified and repair work is needed, there is time to deal with it before the certificate expires and before tenants are affected.
Boiler Servicing Alongside the Safety Check
Many landlords choose to have their boiler serviced at the same time as the gas safety inspection, and this is a sensible approach. Combining both visits means a single appointment for the engineer and a single disruption to the tenants rather than two separate visits.
An annual boiler service involves cleaning the internal components, checking the flue and seals, testing the controls, and identifying any early signs of wear that could develop into a fault later in the year. Keeping up with annual servicing also protects the manufacturer warranty on newer boilers and extends the working life of older units. West London Plumbing can carry out both the CP12 inspection and the boiler service in one visit across all West London postcodes.
Book Your CP12 Gas Safety Inspection in West London
If your gas safety certificate is due for renewal, or if you have recently taken on a tenanted property and need to get the paperwork in order, the West London Plumbing team can help. Our Gas Safe registered engineers work across all W and TW postcodes and can arrange inspections promptly to suit your schedule and your tenants.
Visit our landlord gas safety inspection page for full details of what the CP12 covers, or take a look at our gas safety certificate page for more information on what to expect from the process. To book an inspection or to discuss combining it with an annual boiler service, call us on 020 3561 4415 or contact us online and we will confirm availability the same day.