From the team behind Hampstead Renovations · Est. 2009 · Learn more
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⚠ GAS EMERGENCY — Do not use any switches, sockets, or naked flames. Evacuate immediately if smell is strong. Call 0800 111 999.

Emergency Guide

Gas Leak Emergency — Immediate Action Guide

A gas leak is a life-threatening emergency that requires immediate action. Natural gas is odourless by itself — the distinctive "rotten eggs" smell is added deliberately as a warning. If you smell gas in your NW London home, follow these steps without hesitation. Do not attempt to locate or repair the leak yourself.

Call Now: +44 20 8054 8756

Available 24/7 — average 47-minute response

Step-by-Step Emergency Guide

  1. 1

    Do NOT operate any switches or electrical equipment

    Gas ignites with a tiny spark. Do not turn any light switches on or off, do not use a mobile phone inside the property, do not press any doorbell or alarm buttons, and do not use any naked flame. A single spark can ignite an explosive gas-air mixture.

    ⚠ CRITICAL: This includes pressing a doorbell to leave, using a torch app on your phone, or pressing the button on a smoke alarm. Exit first, then use your phone outside.

  2. 2

    Evacuate everyone from the property immediately

    Get all occupants — including pets — out of the property at once. Leave the front door open as you go (do not use the lock) to help ventilate the space. Move at least 20 metres away from the building.

  3. 3

    Call the National Gas Emergency number

    Once outside and at a safe distance, call the National Gas Emergency Service on 0800 111 999. This is free to call, available 24/7, and they will dispatch an emergency engineer. Do not re-enter the property until the engineer has confirmed it is safe.

  4. 4

    Open doors and windows as you leave (if safe to do so)

    If the smell is faint and you are certain there is no immediate risk of ignition, leave doors and windows open as you evacuate to ventilate the property. If the smell is strong, evacuate immediately without stopping.

  5. 5

    Turn off the gas at the meter (if safe to reach)

    Your gas meter is usually outside the property or in an external cupboard. Turn the handle 90 degrees so it runs across the pipe (perpendicular = off). Only do this if the meter is easily accessible and you do not need to enter the property.

  6. 6

    Call our Gas Safe engineers for follow-up repair

    Once the National Gas Emergency Service has made the property safe and isolated the leak, call us on +44 20 8054 8756 to arrange urgent repair or appliance replacement. All our heating engineers and gas engineers are Gas Safe registered.

Emergency Numbers

  • National Gas Emergency Service

    24/7 — FREE

    0800 111 999

  • Hampstead On Demand Gas Safe Engineers

    24/7

    +44 20 8054 8756

  • Emergency Services (fire/evacuation)

    24/7

    999

Emergency FAQs

What does a gas leak smell like?▼
Natural gas itself is odourless. Energy suppliers add a chemical called mercaptan, which creates a distinctive "rotten eggs" or "sulphur" smell. You may also notice a hissing sound near gas appliances or pipework, dead vegetation in the garden above buried gas pipes, or bubbling in standing water.
Who pays for emergency gas leak repairs?▼
The National Gas Emergency Service will make the property safe and stop the leak at no charge. However, if the leak is from internal pipework, an appliance, or a meter beyond the property boundary, you are responsible for repair costs. Home insurance policies often cover emergency gas work — check your policy.
Can I return home after a gas leak?▼
Only return once the National Gas Emergency engineer has declared the property safe. They will check gas concentrations with specialist equipment. If an appliance is isolated or condemned, it must not be used until a qualified Gas Safe engineer has inspected and repaired or replaced it.
How do I know if my boiler has a gas leak?▼
Signs include: smell of gas near the boiler, yellow or orange flame instead of blue, black marks or soot around the boiler, excessive condensation on windows, or a pilot light that keeps going out. If you notice any of these, do not use the boiler and call a Gas Safe engineer immediately.