Gas Safe registered · CP12 emailed within 24 hours · Landlord portfolios welcome
Gas Safety Certificate London (CP12)
Landlord Gas Safety Certificate for rented properties and HMOs across London, issued by a Gas Safe registered engineer. Every fixed gas appliance tested, tightness test at the meter, certificate emailed within 24 hours. £75–£95 standalone, £160–£220 with a full boiler service.
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What a CP12 is, and why every London landlord needs one
A CP12 is the Landlord Gas Safety Record: the document a Gas Safe registered engineer issues after the statutory annual gas safety check on a rented property. The name is a leftover from the old CORGI form number, which stuck in the trade long after Gas Safe replaced CORGI in 2009, and it is now simply what landlords, letting agents and licensing officers call the certificate. If someone asks you for a CP12, a gas safety certificate, a landlord gas safety certificate or an LGSR, they are all asking for the same single document.
The legal basis is Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998. If you let residential property in England or Wales, and the property contains gas appliances or pipework, you must have every appliance and flue checked for safety at intervals of no more than 12 months, keep a record of the check, and give copies to your tenants. The duty sits with the landlord, not the tenant and not the managing agent, even where an agent handles the booking on your behalf. It applies to houses, flats, HMOs, and in most cases to lodger and licensee arrangements in your own home.
The consequences of letting a record lapse are not theoretical. Missing or expired gas safety records are a criminal offence carrying fines and, in serious cases, custodial sentences. They void most landlord insurance policies. They are a standard inspection item for HMO licensing teams at licence grant and renewal, so a gap in the record trail can attract licence conditions or put a renewal at risk. And in England, failing to give an assured shorthold tenant their gas safety record at the start of the tenancy can block a Section 21 possession claim later, long after the paperwork issue has been forgotten.
We issue CP12 records across every London borough, with our heaviest coverage in North London: Barnet, including Whetstone, Finchley, Hendon and Edgware, Enfield, including Palmers Green, Southgate and Winchmore Hill, plus Haringey, Camden and Islington. Landlord portfolio work is a large part of what we do, so we can usually offer a next day or same week appointment, cluster portfolio visits geographically to keep the per property cost down, and align staggered expiry dates onto a single annual anniversary. The certificate is emailed within 24 hours of the visit and often the same afternoon.
What the engineer checks during a gas safety inspection
Boiler and heating appliances
Combi, system and heat-only boilers are checked for safe operation, correct gas rate against the manufacturer data plate, operating pressure, flame picture, and correct functioning of the safety cut-out devices. Flue gas analysis confirms combustion is within the manufacturer tolerance for CO and CO2. Boilers that have been over-gassed or under-gassed are the most common cause of a defect entry on a CP12.
Gas hob, oven and cooker
Fixed gas cooking appliances are tested for stable ignition, flame supervision device operation (the safety device that shuts off gas if the flame goes out), correct clearance from surrounding surfaces and cupboards, and the condition of the flexible connection hose and its restraining chain. Loose or perished cooker hoses are a frequent At Risk finding in older London rentals.
Gas fires and space heaters
Decorative fuel-effect fires, radiant gas fires and back boilers are tested for combustion performance, correct operation of the oxygen depletion sensor where fitted, and the integrity of the closure plate. Older gas fires in Victorian and Edwardian North London properties are the appliance most likely to be classified Immediately Dangerous, usually because of a blocked or degraded flue.
Flues, chimneys and terminals
Every flue serving a gas appliance is inspected along its accessible length and at the terminal. The engineer checks for correct termination position, adequate clearance from windows and boundaries, no signs of spillage staining, and a satisfactory flue flow and spillage test. Room-sealed boiler flues in flats often need the flue inspection hatches to be accessible, so the engineer may need loft or ceiling void access.
Gas pipework and tightness test
A tightness test is carried out at the meter to confirm the installation holds pressure and there is no gas escape anywhere in the property pipework. The engineer also checks that pipework is adequately supported, protected where it passes through structure, and correctly sleeved and bonded. Main equipotential bonding to the incoming gas service is checked and recorded.
Ventilation and air supply
Open-flued appliances need a permanent air supply to burn safely. The engineer measures existing purpose-provided ventilation against the appliance heat input and confirms nothing has been blocked, sealed or covered. Ventilation blocked by tenants during cold weather, or sealed during a refurbishment, is one of the most common reasons a previously passing appliance fails at the next annual check.
Meter, ECV and installation
The gas meter installation, the emergency control valve and its handle, the meter regulator and the labelling and signage are all checked and recorded. The engineer confirms the emergency control valve is accessible and that a label showing how to turn the gas off is present, which matters when a tenant needs to isolate the supply in a hurry.
Carbon monoxide alarms
The engineer records whether a carbon monoxide alarm is fitted in each room containing a fixed combustion appliance and whether it is in working order. Since October 2022 English landlords must have a CO alarm in every room with a fixed combustion appliance other than a gas cooker, and must repair or replace it when a tenant reports a fault. Similar duties apply in Wales.
Your six legal duties as a landlord, in plain English
Get every appliance checked every 12 months
Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998 requires a landlord to have every gas appliance and flue in a rented property checked for safety at intervals of no more than 12 months. The duty is on the landlord, not the tenant. If you book the new check within the two months before the current record expires, the expiry date rolls forward from the old expiry rather than the new inspection date, so you never lose days by renewing early.
Give existing tenants a copy within 28 days
A copy of the Gas Safety Record must reach every existing tenant within 28 days of the check being carried out. Email is acceptable if the tenant has agreed to receive documents that way. We email the CP12 to the landlord and, on request, direct to the tenant within 24 hours of the visit, so the 28 day clock is never a problem.
Give a new tenant a copy before they move in
Any new tenant must be given a copy of the current Gas Safety Record at the start of the tenancy, before they occupy the property. For assured shorthold tenancies in England this is also a Section 21 precondition, so a missing CP12 at the start of a tenancy can block a possession claim later, even if the property itself was perfectly safe.
Keep records for two years
Copies of every Gas Safety Record must be kept for two years from the date of the check. Local authority licensing teams, HMO licensing officers and insurers all ask for the record trail rather than just the current certificate. We keep a copy of every CP12 we issue and can re-send historic records for any property we have attended.
Use a Gas Safe registered engineer
Only a Gas Safe registered engineer, qualified for the specific appliance types in the property, may carry out the check and issue the record. It has been a criminal offence since 1 April 2009 to work on gas in the UK without Gas Safe registration. A certificate issued by an unregistered person is worthless, will not satisfy a licensing officer, and will not protect an insurance claim.
Take reasonable steps if access is refused
If a tenant will not let the engineer in, the landlord must show they took all reasonable steps to comply. In practice that means a documented trail: written appointment offers, at least two or three attempts on different days and times, recorded delivery or email follow-up explaining the legal duty and the safety risk, and a written record of each attempt. Keep the evidence, and keep trying rather than letting the record lapse quietly.
Cost of a gas safety certificate in London
Every price below is confirmed before the appointment is booked, so the invoice matches the quote. Most landlords take the combined option, because the annual boiler service protects the manufacturer warranty and catches the faults that would otherwise turn into a defect entry on next year's certificate, all within the same visit and the same tenant access arrangement.
| Scope | Price (inc. VAT) | Includes |
|---|---|---|
| Landlord Gas Safety Record (CP12), standalone | £75–£95 | Full property visit, every fixed gas appliance tested, tightness test, CP12 emailed within 24 hours |
| CP12 combined with annual boiler service | £160–£220 | Everything in the standalone CP12 plus a full boiler service, flue gas analysis, service report and warranty renewal |
| Landlord portfolio, 5 or more properties | £95–£125 per property | CP12 plus boiler service per property, consolidated monthly invoicing, standardised checklist, priority scheduling |
| Repair following a defect on the certificate | £130 first hour plus parts | Quoted in writing before work starts, retest and updated record once the fault is cleared |
| Out of hours or weekend appointment | plus £75 premium | Evening and weekend slots for properties where daytime tenant access is not possible |
| Access visit where the tenant is not home | Confirmed before booking | Rebooking is free on the first missed appointment. We log the attempt in writing so you have evidence of reasonable steps |
What happens if an appliance fails the check
Gas engineers do not simply pass or fail an appliance. Unsafe findings are classified under the Gas Industry Unsafe Situations Procedure, and the classification decides what happens next. Understanding the three grades saves a lot of anxiety when the engineer calls you from the property.
ID: Immediately Dangerous
The appliance presents an immediate danger to life or property. With your permission the engineer disconnects and caps it on the spot, or turns off the gas supply, and attaches a warning label. This is not optional and it is not the engineer being difficult: leaving an Immediately Dangerous appliance in service would breach the Gas Industry Unsafe Situations Procedure. Typical causes are a spilling flue, a gas escape, or a failed flame supervision device.
AR: At Risk
One or more defects could make the appliance dangerous. With your permission the engineer turns it off and labels it until the fault is corrected. Common examples are blocked ventilation, a perished cooker hose, an unsatisfactory tightness test on a shared installation, or missing bonding. Once the fault is fixed and retested, the appliance goes back into service and the record is updated.
NCS: Not to Current Standards
The appliance is safe to use but does not meet the standards that would apply if it were installed today. It stays in service and is recorded on the certificate as an advisory. NCS entries are worth acting on at your own pace, because they tend to become At Risk findings in later years as the installation ages.
What a failed check means for the certificate
A CP12 is a record of what was found, not a pass or fail stamp, and it is issued whether or not defects are present. The certificate lists each appliance, the checks carried out, and any defect and the action taken. Where an appliance was disconnected, you get a compliant record showing the appliance is out of service, and a written repair quote so you can decide what to do next. Repairs are quoted before any work starts.
Real London landlord jobs
Barnet N20: four flat conversion, staggered expiry dates
A Whetstone landlord with four flats in one converted house had four different CP12 expiry dates and kept missing renewals. We inspected all four in a single morning and aligned every record to one anniversary date by renewing each within the two month window that preserves the original expiry. One visit a year, one invoice, one date to remember.
Enfield EN2: HMO licence renewal with a failed gas fire
A licensed HMO in Enfield needed a current CP12 for a licence renewal. The decorative gas fire in the ground floor room failed the spillage test and was classified Immediately Dangerous. It was capped and labelled on the day, the CP12 was issued showing the appliance out of service, and the fire was removed and the chimney sealed the following week. Licence renewal went through on the original record.
Haringey N8: new tenancy starting in three days
A Crouch End landlord exchanged on a new tenancy with no current gas safety record. We attended the next morning, tested the boiler and hob, and emailed the CP12 the same afternoon, so the tenant received their copy before the tenancy start date and the Section 21 precondition was satisfied from day one.
Landlord gas safety certificates across every London borough
Frequently asked questions about gas safety certificates and CP12
What is a CP12?
Is a CP12 the same as a gas safety certificate?
How much does a gas safety certificate cost in London?
How often do I need a gas safety certificate?
What if my tenant refuses access?
What does the engineer actually check?
How long does a gas safety check take?
What happens if an appliance fails the check?
Do I need a CP12 if I rent to a lodger or let a room in my own home?
How long do I have to keep the certificates?
Do I need a gas safety certificate to sell my house?
Which areas do you cover for landlord gas safety checks?
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HMO hot water cylinders
G3 cylinder compliance for licensed HMOs, alongside the annual gas safety record.
Book your CP12 today
Gas Safe registered engineer, certificate emailed within 24 hours, portfolio pricing for five or more properties. Next day appointments across North London.
Call 020 7101 0629