The term "CP12" is used constantly in the world, but many property owners are still unclear about exactly what it is, what it covers, and why it matters so much. This complete guide explains everything you need to know about the CP12 Gas Safety Certificate — what the inspection involves, what's checked, and how to get one at the best price in London.
Contents
What is a CP12?
"CP12" refers to the form number (Check/Proforma 12) originally used by gas engineers to record a Gas Safety Record (LGSR). While the official name is " Gas Safety Record," the shorthand "CP12" is universally used in the industry to refer to the annual gas safety inspection and certificate required for all rental properties with gas appliances.
The CP12 is a legal document produced by a Gas Safe registered engineer after inspecting all gas appliances, pipework, and flues at a property. It confirms whether each appliance has passed or failed the safety check, and must be renewed every 12 months.
The legal basis for the CP12 is the Gas Safety (Installation and Use) Regulations 1998, Regulation 36, which places a duty on to ensure the safety of gas installations in properties they let.
What Does the CP12 Inspection Cover?
During a CP12 inspection, the Gas Safe engineer will check every gas appliance, fitting, and connection at the property. Specifically, the engineer will inspect:
1. Gas Boiler
- Burner operation and ignition
- Combustion analysis (flue gas testing)
- Safety controls and pressure relief
- Flue integrity and terminal position
- Hot water production (if combination boiler)
- Ventilation adequacy
2. Gas Hob or Cooker
- Burner operation and shut-off valves
- Flame supervision device (FSD) testing
- Stability and anti-tilt mechanisms
- Flexible connection integrity
3. Gas Fire or Wall Heater
- Pilot light and ignition
- Combustion performance
- Flue and ventilation
- Clearances from combustibles
4. Gas Pipework and Meter
- Visual inspection of all exposed pipework
- Pressure test for gas tightness
- Meter connections and emergency control valve
- Presence of bonding connections
How Long Does a CP12 Inspection Take?
| Property Type | Appliances | Typical Duration |
|---|---|---|
| Studio / 1-bed flat | 1 (boiler only) | 30–45 minutes |
| 1–2 bed flat | 2 (boiler + hob) | 45–60 minutes |
| 3-bed house | 3 (boiler, hob, fire) | 60–90 minutes |
| HMO property | 4+ | 90+ minutes |
Pass or Fail — What Happens Next?
Once the inspection is complete, each appliance is recorded as one of the following:
- ✅ PASS (ID — Immediately Dangerous — No): The appliance is safe and the CP12 is issued
- ⚠️ PASS with recommendations: The appliance is currently safe but attention is advised
- ❌ FAIL (Immediately Dangerous or At Risk): The appliance poses a safety risk and must be repaired or isolated
If any appliance is classified as "Immediately Dangerous," the engineer is legally obligated to disconnect it from the gas supply and leave a warning label. The appliance cannot be used until repairs have been completed and the appliance re-inspected.
Your Legal Obligations as a
Under the Gas Safety (Installation and Use) Regulations 1998:
- You must arrange a CP12 inspection every 12 months
- You must use a Gas Safe registered engineer
- You must provide a copy to new tenants before they move in
- You must provide a copy to existing tenants within 28 days of the inspection
- You must retain records for at least 2 years
How Much Does a CP12 Cost in London?
With Cheapest Certificates, CP12 prices are:
| Service | Price (inc. VAT) |
|---|---|
| Gas Safety Certificate (1 appliance) | £49 |
| Gas Safety Certificate (2 appliances) | £59 |
| Gas Safety Certificate (3 appliances) | £69 |
| CP12 + Boiler Service bundle | £109 |
Frequently Asked Questions
What is a CP12 certificate?
CP12 is the colloquial name for a Gas Safety Record (LGSR). It is the certificate issued by a Gas Safe engineer confirming that all gas appliances and pipework at a rental property have been inspected and are safe.
Who can carry out a CP12 inspection?
Only a Gas Safe registered engineer.
How long is a CP12 valid for?
12 months. It must be renewed annually regardless of when the last inspection took place.
Do I need a CP12 if my tenant has their own gas appliances?
If the appliances were there when you let the property, yes. If tenants brought their own appliances, your responsibility depends on whether they are connected to your gas supply — seek specific legal advice in this case.
How much does a CP12 cost in London?
From £49 with Cheapest Certificates for a property with one gas appliance. Prices increase with additional appliances.