Knowing what to do in the first few minutes of a gas leak can save lives. This guide covers the immediate steps, who to call, and what not to do.
Immediate Steps
If you smell gas or suspect a gas leak:
- Do not turn any electrical switches on or off — a spark can ignite gas
- Extinguish all naked flames — candles, matches, cigarettes
- Open windows and doors to ventilate the property
- Turn off the gas supply at the emergency control valve (ECV) — this is usually next to the gas meter. Turn the handle 90° so it is perpendicular to the pipe
- Leave the property immediately with all occupants
- Call the National Gas Emergency Service on 0800 111 999 — this is free, available 24/7
- Do not re-enter until the emergency service has attended and confirmed it is safe
What NOT to Do
- Do not use your mobile phone inside the property — use it once you are outside
- Do not operate any electrical switches
- Do not use doorbells or intercoms inside the building
- Do not light matches or lighters
- Do not attempt to find or fix the leak yourself
The National Gas Emergency Service
The National Gas Emergency Service (run by National Gas) will attend to make the property safe. They will locate the leak, isolate the relevant supply if needed, and advise on what further work is required. This service is free for safety purposes.
After the Emergency
Once the emergency service has attended and confirmed the immediate danger is resolved, you will need a Gas Safe registered engineer to identify and repair the faulty appliance or pipework before gas is reinstated. The National Gas emergency team can isolate supply but they do not carry out repairs to boilers or appliances.
Recognising a Gas Leak
- Smell of rotten eggs or sulphur (the odorant added to natural gas)
- Hissing sound near a gas pipe or appliance
- Dying plants near a suspected leak underground
- Physical symptoms: dizziness, nausea, headaches, fatigue in the building
Frequently asked questions
What number do I call for a gas emergency in London?
0800 111 999 — this is the National Gas Emergency Service, available 24 hours a day, 365 days a year. The call is free.
Should I turn off the gas at the meter if I smell gas?
Yes — turning off the emergency control valve at the meter is one of the first steps. Turn the handle 90° so it is at a right angle to the pipe, then open windows and leave the property.
Can I turn the gas back on myself after a suspected leak?
No — do not restore the gas supply yourself. Wait for the emergency service to attend and confirm it is safe, and then have a Gas Safe registered engineer carry out any necessary repairs and testing before gas is reinstated.
Is a smell of gas always a leak?
Not always — a brief smell can occur if a pilot light has gone out or an appliance has been switched on without igniting. However, treat any gas smell as a potential emergency until it has been confirmed safe by a professional.