How the UK gas network works
Gas does not travel straight from your supplier to your home. It moves through two layers of pipes owned by network companies: a high-pressure transmission backbone that crosses the country, and the regional distribution networks that run the final pipes to your meter. Here is how the two fit together, and who to call in an emergency.
- 7,660 km
- of high-pressure transmission pipe
- 4
- gas distribution networks in Great Britain
- 3
- separate networks in Northern Ireland
- 24/7
- free national gas emergency line
Terminal to meter
Follow the gas to your home
Four stages connect a coastal terminal to your hob. Tap any stage to see what happens and who owns it. Network companies own everything up to your meter; your supplier only sells the gas.
1. Terminals
Gas first lands at coastal terminals: from North Sea fields, from ships at LNG ports such as the Isle of Grain and Milford Haven, and through undersea interconnectors from Norway and the continent. It is cleaned, measured and odorised here before it ever enters a pipe.
Owned by: Terminal operators & shippers2. Transmission
The National Transmission System carries the bulk of the gas across the country at very high pressure (up to 94 bar) through around 7,660 km of welded steel pipe. National Gas Transmission runs it, feeding power stations, large industry and the hand-over points where regional networks take over.
Owned by: National Gas Transmission3. Distribution
At pressure-reduction points the gas is stepped down and handed to a regional Gas Distribution Network. There are four GDNs across Great Britain and three separate networks in Northern Ireland. They own the lower-pressure mains that run under the streets to your neighbourhood.
Owned by: 4 GB networks + 3 in Northern Ireland4. Your meter
A final low-pressure service pipe (around 21 millibar at the meter, a gentle pressure that is safe for your boiler and hob) brings the gas into your home. The network owns this pipe and the meter point. Your supplier does not own any pipes; it simply sells you the gas that flows through them.
Owned by: Network (pipe) · Supplier (the gas)Two layers, two hubs
Transmission and distribution
The gas network splits into a national high-pressure backbone and the regional networks that branch off it. Each has its own guide.
The national backbone
Transmission
The high-pressure National Transmission System: around 7,660 km of steel pipeline operated by National Gas Transmission, moving gas from coastal terminals to power stations, industry and the regional networks.
Explore transmissionThe pipes to your meter
Distribution
The regional networks that own the lower-pressure pipes feeding your meter: four Gas Distribution Networks across Great Britain, plus three separate networks in Northern Ireland. Interactive UK map.
Explore distribution| Transmission | Distribution | |
|---|---|---|
| What it does | Moves bulk gas across the country | Routes gas locally to your street |
| Pressure | Very high (up to 94 bar) | Stepped down to low (about 21 mbar at the meter) |
| Who runs it | National Gas Transmission (one operator) | 4 GDNs in GB + 3 in Northern Ireland |
| Pipes | Large welded steel, cross-country | Smaller mains and service pipes under streets |
| Reaches | Power stations, big industry, off-take points | Homes and local businesses |
If you smell gas, call the emergency line
The emergency service is free and answered 24 hours a day, every day. It is run by the networks, not your supplier.
National Gas Emergency Service (Great Britain)
0800 111 999
In Northern Ireland, call 0800 002 001 instead.
- Open doors and windows to let the gas escape;
- turn off the gas at the meter if it is safe to do so;
- do not use light switches, naked flames or anything that could cause a spark;
- leave the property and call the emergency line from outside.
Common questions
The UK gas network, answered
The pipes are owned by network companies, not by your energy supplier. A high-pressure backbone called the National Transmission System (run by National Gas Transmission) carries gas across the country, and a regional Gas Distribution Network owns the lower-pressure pipes that reach your meter. Your supplier only sells you the gas that travels through those pipes.
Transmission is the national high-pressure backbone (up to 94 bar) that moves large volumes of gas long distances. Distribution is the regional, lower-pressure layer that branches off it and delivers gas to individual streets and meters. Think of transmission as the motorway and distribution as the local roads.
No. Your gas network is a regulated regional monopoly fixed by your address, just like your electricity distributor. You can switch the supplier that bills you whenever you like, but the company that owns and maintains the pipes always stays the same.
In Great Britain, call the National Gas Emergency Service free on 0800 111 999, 24 hours a day. In Northern Ireland the number is 0800 002 001. The line is run by the networks, not your supplier. Open doors and windows, do not touch electrical switches, and leave the property before you call.
No. Suppliers (British Gas, Octopus, E.ON Next and so on) buy gas wholesale and bill you for what you use. The networks build, maintain and repair the pipes and respond to leaks and emergencies. That is why an emergency call goes to the network line, not to your supplier.