DNO, IDNO, ICP and IGT: Who Actually Does What
Published 8 October 2026 · Reviewed by Muhammad Khan
Utility connections have an acronym problem.
You start a development, and within a fortnight you are dealing with a DNO, possibly an IDNO, quite likely an ICP, maybe an IGT, definitely a GDN, and someone has mentioned a UIP. They all sound similar. Several of them do genuinely overlapping things. And nobody explains the difference, because everyone in the industry assumes you already know.
So here is the whole map, in one place, with the bit that actually matters to you flagged at the end.
Start with the one question that sorts everything
Every organisation in this space does one of three things, and once you know which, the confusion mostly disappears.
- Owns the network. Collects charges from it, maintains it, is responsible for it long term.
- Builds the connection. Designs and constructs new infrastructure, then hands it over. Owns nothing afterwards.
- Sells you the energy. Nothing to do with pipes, cables or construction at all.
Almost every mix up comes from putting an organisation in the wrong one of those three boxes.
The electricity side
DNO, Distribution Network Operator
An owner. The DNO owns and operates the electricity distribution network in a defined geographical region, licensed by Ofgem. There are fourteen licence areas across England, Scotland and Wales.
The DNO carries electricity from the transmission grid to homes and businesses in its region. On a new connection it does the non contestable works, which only it is permitted to do: deciding the point of connection, designing any wider network reinforcement, and making the final live connection.
It can also build the contestable works for you, if you ask it to. Most people ask it to, mainly because they do not realise there is another option.
ICP, Independent Connection Provider
A builder. An ICP is an accredited contractor that designs and constructs new electricity connections. Cable laying, jointing, ducting, civils, substation installation.
An ICP does not own a network and never will. It builds infrastructure that somebody else adopts. Its accreditation is NERS, administered by Lloyd's Register, and it can only work within the scope that accreditation covers.
This is the competitive part of the market. An ICP competes with the DNO on the contestable works.
IDNO, Independent Distribution Network Operator
An owner, like a DNO, but not regional. IDNOs operate nationally, adopting new networks wherever they are built.
Both are licensed and regulated by Ofgem, and IDNO licence conditions require the same service levels and the same guaranteed performance standards that apply to DNOs. Customers on an IDNO network can still choose any electricity supplier they like.
The commercial difference is the reason IDNOs exist and the reason developers care. Because an IDNO wants to own your completed network, it will pay you for it. That payment is the asset value, made on energisation. Traditionally a developer built the network and simply handed it to the DNO for nothing, giving away a long term revenue generating asset for free.
There is one structural detail worth knowing. If the DNO builds your connection, only the DNO can adopt it. If an ICP builds your connection, either a DNO or an IDNO can adopt it. The choice only exists on the ICP route.
The gas side, which works the same way with different letters
GDN, Gas Distribution Network
The gas equivalent of a DNO. An owner. A GDN owns and operates the gas distribution network in its region, taking gas from the national transmission system and delivering it to homes and businesses. There are four GDNs in Great Britain, covering eight regions across England, Scotland and Wales, all regulated by Ofgem.
IGT, Independent Gas Transporter
The gas equivalent of an IDNO. An owner, operating independently rather than regionally.
IGTs are private companies licensed by Ofgem to own and operate gas networks to the same safety, performance and service standards as a GDN. They came about after gas market deregulation ended the old British Gas monopoly.
An IGT network connects into the GDN network at a defined point, and gas flows through it to the properties on it. The IGT owns and maintains the pipes but does not own the gas. It collects a regulated fee from the energy supplier for transporting it, exactly as a GDN does. IGTs also hold agreements with the regional GDN so that emergencies are handled through the National Gas Emergency Service in the normal way.
Two things surprise people about IGTs. First, the scale: roughly a million properties in the UK are connected to IGT networks rather than GDN networks. Second, how likely you are to be on one. New housing and commercial developments make up the largest share of the IGT market, and if a property was built since around 2006 there is a fair chance its gas infrastructure belongs to an IGT.
And like IDNOs, IGTs pay asset values on the networks they adopt.
UIP, Utility Infrastructure Provider
A builder, on the gas side and often across multiple utilities. A UIP constructs the new network, and an IGT or IDNO then adopts it.
In practice the ICP and UIP labels overlap heavily, and many companies are both. Gas construction accreditation is GIRS, again administered by Lloyd's Register.
The water side, briefly
Water follows the same competitive logic with its own vocabulary.
The incumbent water company is the regional owner, the equivalent of a DNO or GDN.
An SLP, or self lay provider, is the builder. Accredited under WIRS, it lays new water mains and makes service connections instead of the water company doing it, which is where the cost saving on water connections comes from.
A NAV, or New Appointment and Variation, is the alternative owner. Appointed by Ofwat to serve a specific site, it owns and operates the water network there instead of the incumbent, usually buying water wholesale from the incumbent at the site boundary. Same regulated standards, same protections for residents.
The one that is in none of these boxes
Your energy supplier is the company you buy electricity or gas from and who sends your bill. Octopus, EDF, British Gas, Scottish Power.
They do not build connections. They do not own distribution networks. They have no involvement in your development's infrastructure whatsoever.
This confusion costs people weeks. Phoning your supplier about a new connection is like phoning a supermarket about the state of the road outside it. Reasonable enough mistake, entirely the wrong organisation.
The whole thing in one table
| Who | Utility | Role | Can you choose? |
|---|---|---|---|
| DNO | Electricity | Regional network owner, does non contestable works | No, fixed by location |
| ICP | Electricity | Builds the connection, accredited under NERS | Yes |
| IDNO | Electricity | National network owner, pays asset value | Yes, via the ICP route |
| GDN | Gas | Regional network owner | No, fixed by location |
| UIP | Gas and multi utility | Builds the network, accredited under GIRS | Yes |
| IGT | Gas | Independent network owner, pays asset value | Yes, via the UIP route |
| Water company | Water | Regional network owner | No, fixed by location |
| SLP | Water | Self lay builder, accredited under WIRS | Yes |
| NAV | Water | Alternative site network owner | Yes, on larger schemes |
| Supplier | All | Sells you the energy | Yes, separate decision |
What this means in practice
Read the right hand column again, because that is the whole point of this article.
Your regional network owner is fixed. You cannot choose your DNO, your GDN or your incumbent water company. They are determined by where your site is, and you will be dealing with them whatever else you decide.
Everything else is a decision you get to make. Who builds the connection. Who adopts and owns the completed network. Whether that adoption comes with an asset value payment or whether you hand the asset over for nothing.
Most developers make those decisions by default, without realising a decision was being made. They go to the regional network owner, accept the quote, hand over the completed asset, and never learn that the other columns existed.
The acronyms are not the complicated part. The complicated part is that nobody tells you which of them you were allowed to pick.
Not sure which route suits your site?
Air Utilities is accredited under NERS, GIRS and WIRS, which means we can build across electricity, gas and water, and arrange adoption with a DNO, IDNO, IGT or NAV depending on what suits your scheme. Tell us about the project and we will set it out plainly.