Smell gas at home in London? What to do first

Do these things now

If you can smell gas, follow these steps in this order. They come from Cadent’s own advice. Cadent runs the gas network across North London, so it is their engineers who attend in most of the areas this site covers.

1. Get people out if the smell is strong, if anyone feels unwell, or if you cannot do the steps below safely.
2. Open doors and windows to let the gas out.
3. Do not turn any switches on or off. That includes lights, the doorbell and plugs. Do not use anything that could spark.
4. Do not light a flame. No matches, lighters, candles or cigarettes. Do not use the hob.
5. Turn off the gas at the emergency control valve, usually next to the meter, if you can reach it safely. The handle turns 90 degrees. If the smell is coming from a cellar or basement, do not go down there. Leave the building instead.
6. Call 0800 111 999 once you are safe. It is free and open all day and night.
7. Wait for the all clear from the emergency engineer before going back in.

If anyone is unwell, call 999 as well.

Why London homes make this harder

The steps are the same everywhere. What changes in north and east London is where the meter is.

In a Victorian terrace in Stoke Newington, Clapton or Kentish Town that has been split into two or three flats, the gas meters can be anywhere. Under the stairs. In a cellar or front vault. In a cupboard in the shared hall. In a row in the basement. Upstairs tenants often do not know where their own valve is, and it may be behind a door they do not have a key for.

In purpose built blocks the meters may be in a riser cupboard on each landing or in a ground floor meter room. In Walthamstow’s Warner half houses, each of the two flats has its own front door, so the two supplies are separate but close together.

That is why the best time to find your emergency control valve is now, while nothing is wrong. Our guide to finding your gas emergency control valve in a London flat goes through the usual places.

What happens after you call

Stage	Who	What they do
Call	National Gas Emergency Service, 0800 111 999	Takes details and tells you what to do while you wait
Attend	Emergency engineer from the local network (Cadent in North London)	Finds the source and makes it safe, which may mean turning off or capping the supply
Make safe	Same engineer	May leave an appliance or the whole supply off, with a warning label
Repair	A Gas Safe registered engineer you choose	Repairs or replaces the faulty appliance or pipe, tests and turns it back on

Cadent’s engineers carry ID. They need to get into the property to make it safe, so if you have left, stay nearby.

Cadent says plainly that extra work on appliances such as ovens, boilers and fires needs a Gas Safe registered engineer. That is the point where you call someone like London Gas Engineers. Our gas leak page explains how that follow up visit runs.

Smell outside, not inside

If the smell is in the street or front garden, Cadent says to call 0800 111 999 as soon as you can, keep away from naked flames and wait for an engineer to investigate. Gas mains run under most north London streets, and a smell outside is just as important to report as one in your kitchen.

Common causes once it is safe

After the emergency engineer has made things safe, the follow up usually finds one of these:

• A hob burner left on without a flame
• A loose or worn cooker hose behind a freestanding cooker
• A leaking joint on old pipework, often under floors in older houses
• A fault on a boiler, gas fire or water heater
• Damage from building work, such as a nail or screw through a pipe

Gas Safe Register’s home improvement advice reminds people to check where gas pipes run before drilling or lifting floorboards. In older London houses that have been converted more than once, pipe routes are not always obvious.

Smell gas but feel ill?

Natural gas has a smell added to it. Carbon monoxide does not. Cadent notes that a gas leak can cause dizziness, fatigue, nausea and headaches, and that if you have those symptoms but cannot smell gas, it could be carbon monoxide.

The NHS lists the main symptoms of carbon monoxide poisoning as headache, dizziness, feeling or being sick, and feeling weak. Get into fresh air. Call 999 or go to A&E if someone is very unwell. Then call 0800 111 999. A working CO alarm is the only way to know CO is there, which is why our carbon monoxide alarms page is worth reading.

After the all clear

Once your supply is back on, or an appliance has been left off, book the repair with a Gas Safe registered engineer. Ask to see their ID card and check the work categories match the appliance. If you rent, tell your landlord or agent straight away. The repair is usually their responsibility, and they need it recorded alongside their annual gas safety record.