Understanding Your Gas Meter in London: Readings, Emergency Shutoff & Safety

Your gas meter is the boundary between the national grid and your home's gas supply. Knowing how to read it, where to find the emergency shutoff, and what to do if something goes wrong can prevent dangerous situations and inaccurate energy bills.

Types of Gas Meter in London Properties

London properties typically have one of three meter types:

• Imperial (cubic feet) meters: Older meters, often found in pre-1990s properties, displaying four black digits followed by two red digits. Only the four black digits are used for billing.
• Metric (cubic metres) meters: Modern standard, displaying five digits. All five are used for the reading.
• Smart meters (SMETS1 or SMETS2): Digital display, often cycling through multiple screens. Press the display button to find the meter reading screen — usually labelled "IMP KWH" or showing a row of digits.

How to Take an Accurate Reading

For a metric meter, read the five digits from left to right and ignore any figures after the decimal point (shown in red). For an imperial meter, read only the four black digits from left to right and ignore the red ones. Submit your reading to your supplier as: the digits you recorded, followed by a note of whether it is cubic feet or cubic metres.

If your supplier has been issuing estimated bills, submitting an actual reading can correct significant over- or under-charges — a common issue in London's frequently changing rental market where suppliers default to estimates between tenancies.

Where Is the Emergency Gas Shutoff?

The emergency control valve (ECV) is the manual lever that isolates the entire gas supply to your property at the meter. It is almost always located:

• Immediately next to or attached to the gas meter itself
• In a meter box on the external wall (common in London terraces and purpose-built flats)
• In a communal meter cupboard in apartment buildings

The valve is open when the handle is parallel to the pipe, and closed when it is at 90 degrees (perpendicular) to the pipe. Familiarise yourself with its location before you ever need it — finding it in an emergency wastes critical seconds.

If You Smell Gas: What to Do

A gas smell in or around your property is a potential emergency. Follow this sequence without exception:

1. Do not operate any electrical switches — no lights, no sockets, no appliances. Electrical sparks can ignite gas.
2. Do not use your mobile phone inside the property — take it outside first.
3. Open doors and windows to ventilate the space.
4. Turn off the gas at the emergency control valve next to the meter.
5. Leave the property and stay away from the building.
6. Call the National Gas Emergency Service: 0800 111 999 — this line operates 24 hours a day, 365 days a year and is free from any phone. They will dispatch a National Grid engineer to your property, usually within the hour.

Do not re-enter the property until given the all-clear by the attending engineer. Do not attempt to locate the gas leak yourself.

Carbon Monoxide: The Invisible Risk

A gas smell indicates unburnt gas escaping — a different but equally serious risk is carbon monoxide (CO) from incomplete combustion. CO has no smell. Every London property with a gas appliance must have at least one audible CO alarm, ideally within 1–3 metres of each gas appliance. If your CO alarm sounds, treat it as a gas emergency: leave immediately and call 0800 111 999.

Annual Gas Safety Checks

Landlords in London are legally required to arrange an annual Gas Safety Check (CP12) on all gas appliances and flues by a Gas Safe registered engineer. Owner-occupiers are strongly advised to do the same. Annual servicing of your boiler, cooker, and any gas fires maintains safety certification and preserves appliance warranties.

If you are unsure whether your gas appliances have been recently serviced, check the Gas Safe Register website to verify an engineer's credentials before booking.