A gas safety certificate, or CP12, is the landlord gas safety record issued after a Gas Safe registered engineer checks every gas appliance, fitting and flue in a rented home. Landlords must renew it every 12 months and give existing tenants a copy within 28 days. BritCertify carries out checks across London from £75 inc. VAT, with the record emailed the same day.
What is a CP12 gas safety certificate?
CP12 is the name of an old form that agents still use for what is now called the landlord gas safety record. It records the checks a Gas Safe registered engineer has made on every gas appliance, fitting and flue a landlord provides, and whether each one is safe to use.
The legal duty comes from regulation 36 of the Gas Safety (Installation and Use) Regulations 1998. Landlords must:
- have every gas appliance, fitting and flue they provide checked for safety every 12 months;
- use a Gas Safe registered engineer, as only registered engineers may legally work on gas appliances;
- give a copy of the record to existing tenants within 28 days of the check;
- give a copy to new tenants before they move in;
- keep records for at least 2 years.
Since April 2018, a check carried out up to 2 months before the deadline can keep the original expiry date, so you can renew early without losing months. The HSE’s guidance for landlords sets out the full duty. Gas work is carried out by Gas Safe registered engineers (Gas Safe reg. 962998). Always ask to see the engineer’s Gas Safe ID card, and you can check any engineer on the Gas Safe Register.
What does a gas safety check include?
The engineer tests the installation pipework for leaks, then checks each appliance’s operation, flue and ventilation. A gas cooker or hob counts as an appliance on the record, just like a boiler or gas fire.
| Check | What it confirms |
|---|---|
| Tightness test | The installation pipework from the meter is not leaking gas |
| Gas rate or operating pressure | Each appliance is burning the right amount of gas |
| Flue flow and spillage tests | Combustion products leave the building safely rather than entering the room |
| Combustion analysis | Flue gas readings are within the manufacturer’s limits where a reading is required |
| Ventilation | Appliances that need an air supply have adequate, unobstructed vents |
| Safety devices | Flame supervision on hobs, ovens and fires, and boiler safety controls, work correctly |
| Condition and siting | Flue terminals, cooker stability brackets and appliance locations are safe |
A gas safety check is not a service. It confirms the appliances are safe on the day, but it does not include cleaning or maintaining the boiler. You can combine the two on one visit with our boiler service and repair option, priced at £159 inc. VAT including the certificate.
Which appliances does the landlord have to cover?
Every gas appliance, fitting and flue you provide for the tenant’s use. That includes the boiler, cooker or hob, gas fires and water heaters, plus the pipework from the meter. Appliances a tenant owns are the tenant’s responsibility, but if our engineer sees a dangerous tenant-owned appliance, it is still dealt with under the unsafe situations procedure and you are told. If a gas fire is no longer wanted, having it disconnected and capped by a Gas Safe registered engineer means it no longer needs an annual appliance check.
How much does a gas safety certificate cost in London?
The price depends on how many gas appliances the property has. A typical flat with a combi boiler and a gas hob has two appliances and costs £75 inc. VAT. Three appliances cost £85 and four cost £95, with £10 for each appliance beyond that, which mainly affects HMOs with several cookers.
Landlords who also need an electrical inspection can book our landlord gas and electrical bundle, from £154 inc. VAT for a gas safety certificate and EICR together. Ask about multi-certificate discounts if you manage several properties.
What do our engineers find in London rental properties?
- Victorian and Edwardian conversions: boilers squeezed into kitchen cupboards, flues discharging into narrow lightwells close to neighbours’ windows, and decorative gas fires in period fireplaces where the condition of the chimney is unknown.
- New-build and converted flats: boiler flues running through ceiling voids with no inspection hatches. If the engineer cannot see the flue joints, they cannot confirm the flue is safe, and the boiler may be classed At Risk until hatches are fitted.
- Kitchen refits: cookers installed without a stability bracket, and new units blocking the ventilation an older appliance relies on.
- HMOs: several cookers in shared kitchens, boilers inside bedrooms, and meters in locked communal cupboards that need arranging in advance.
What happens if an appliance fails?
The engineer records the problem and follows the Gas Industry Unsafe Situations Procedure, which sets out what must happen at each level of risk.
| Classification | Meaning | What the engineer does |
|---|---|---|
| Immediately Dangerous (ID) | An immediate risk to life or property | With your permission, disconnects the appliance and attaches a warning label |
| At Risk (AR) | Faults that could become dangerous | With your permission, turns the appliance off and labels it |
| Not to Current Standards (NCS) | Installed to an earlier standard but not unsafe | Records it and advises on improvement |
An appliance labelled ID or AR must not be used until it has been repaired and re-checked. We explain the fault in plain terms, quote for the repair and update the record once the appliance is safe. If tenants lose heating or hot water in cold weather, provide temporary heaters while repairs are arranged and keep them informed in writing.
What else should landlords check at the same visit?
Carbon monoxide and smoke alarms. Under the Smoke and Carbon Monoxide Alarm (Amendment) Regulations 2022, landlords must have a CO alarm in any room used as living accommodation that contains a fixed combustion appliance, excluding gas cookers, and at least one smoke alarm on every storey with living accommodation. Alarms must be checked on the first day of each new tenancy, and penalties reach £5,000. Our smoke alarm and fire safety certificate covers this.
Records matter more than ever. Under the Renters’ Rights Act 2025, landlords must register each rented property on the Private Rented Sector Database and provide the gas safety record and its issue date. London registration opens on 15 July 2027 and must be completed by 14 October 2027, so keep the current record somewhere you can find it.
How do you prepare for the visit?
- Give tenants written notice and confirm someone will be home to provide access.
- Clear the boiler cupboard, the area around the meter and the cooker, and make sure any flue boxing can be reached.
- In flats, arrange access to communal meter cupboards and tell us about parking.
- Have the previous record to hand so the engineer can compare results.
Managing several properties? Request a quote with each property’s renewal date, and we will schedule the checks to suit.
Gas safety certificate prices in London (inc. VAT)
| Option | Price (inc. VAT) | Notes |
|---|---|---|
| 1–2 gas appliances | £75 | For example a boiler and a hob |
| 3 gas appliances | £85 | Includes pipework tightness test |
| 4 gas appliances | £95 | Includes pipework tightness test |
| Each appliance beyond 4 | +£10 | Common in HMOs with several cookers |
| Gas safety certificate + boiler service | £159 | Both completed on one visit |
All prices include VAT. A gas cooker or hob counts as an appliance. Central London parking or Congestion Charge may be added; we always confirm before booking.
Book this serviceWhat's included
- Tightness test of the gas installation pipework
- Safety checks on every landlord-provided appliance and flue
- Ventilation and safety device checks
- Landlord gas safety record emailed the same day
- Plain-English explanation of any defects
- Fixed quote for any repairs needed
- Option to add a boiler service for £159 in total
How it works
Book
Tell us how many gas appliances the property has. We confirm the price, an arrival window and any parking charges.
Safety checks
A Gas Safe registered engineer tests the pipework for tightness and checks each appliance's gas rate, flue, ventilation and safety devices.
Record issued
Your landlord gas safety record is emailed the same day, listing every appliance checked and any defects found.
Fix and re-check
If anything is unsafe, we explain the classification, quote for repairs and update the record once the work is done.
Gas Safety Certificate (CP12): frequently asked questions
How much is a gas safety certificate in London?
A landlord gas safety certificate with BritCertify costs £75 inc. VAT for 1–2 appliances, £85 for 3 and £95 for 4, plus £10 for each appliance beyond 4. A gas safety certificate combined with a boiler service costs £159. Central London parking or Congestion Charge may be added; we always confirm before booking.
How long is a gas safety certificate valid?
A landlord gas safety record is valid for 12 months. You can have the next check carried out up to 2 months before the deadline and still keep the original expiry date, which stops the anniversary drifting earlier each year. Keep each record for at least 2 years and give tenants a copy within 28 days of the check.
Who can issue a gas safety certificate?
Only a Gas Safe registered engineer who is qualified for the type of appliance being checked. Ask to see the engineer's Gas Safe ID card when they arrive; the back of the card shows the categories of work they are qualified to carry out. You can also check an engineer's registration on the Gas Safe Register website before the visit.
Is a gas safety check the same as a boiler service?
No. A gas safety check confirms that appliances, pipework and flues are safe to use, which is the legal requirement for landlords. A boiler service goes further: the engineer inspects and cleans components and checks performance against the manufacturer's instructions, which helps prevent breakdowns. Booking both together costs £159 inc. VAT with BritCertify.
Do I need a gas safety certificate if the flat only has a gas hob?
Yes. Any gas appliance, fitting or flue you provide for tenants falls under regulation 36, including a hob or cooker, and the pipework from the meter is tested as well. A hob-only property falls into our 1–2 appliance price of £75 inc. VAT. If the gas supply is capped and not in use, tell us before booking.
What if my tenant will not give access for the check?
Keep trying and keep evidence. Write to the tenant explaining that the check is a legal safety requirement, offer several appointment times and keep copies of every letter, email and text. Being able to show you took reasonable steps matters if the record lapses. Do not enter without permission, and take advice if access is repeatedly refused.
Sources and official guidance
Written and checked by the BritCertify technical team. Last reviewed 6 October 2026.