The short answer: EFM (Ethernet in the First Mile, often called Ethernet First Mile) is a business internet connection that bonds between two and eight copper telephone pairs from your local exchange to give the same speed in both directions, usually up to about 35 Mbps, with a business service level agreement. Today it is outpaced by full fibre and fibre leased lines, and it runs on the copper network Openreach is retiring, so most businesses should treat EFM as a stopgap rather than a long-term choice.
In this guide:
- What is EFM?
- How does EFM work?
- How fast is EFM?
- EFM vs FTTC, full fibre and fibre leased lines
- Is EFM being switched off?
- Is EFM still worth it?
- If you have an EFM line now
- Frequently asked questions
- Sources
What is EFM?
EFM stands for Ethernet in the First Mile. The name comes from the IEEE 802.3ah standard, approved in 2004, which set out ways to carry Ethernet over the “first mile” between a telecoms network and a customer’s building. In the UK, the term almost always means one thing: a business connection delivered over several ordinary copper telephone pairs, bonded together to act as one line.
You will see EFM sold under several names, including Ethernet First Mile, EFM leased line, copper leased line, bonded copper and Ethernet over copper. They all describe the same idea. What sets EFM apart from broadband is how it behaves:
- Symmetrical speed. Uploads are as fast as downloads, which matters for cloud backups, video calls and remote access.
- Usually uncontended. The bandwidth is yours rather than shared with neighbouring premises, so it should not slow down at busy times.
- Business service level agreement. Providers commit to fix time targets, often with compensation if they miss them, rather than broadband’s best efforts.
- Resilience built in. If one copper pair develops a fault, the line usually stays up at a lower speed on the remaining pairs.
How does EFM work?
An EFM line uses the same kind of copper pairs that carry a traditional phone line. Instead of one pair, the provider connects several, usually between two and eight, from your premises back to equipment in your local telephone exchange. Each pair carries a symmetrical DSL signal, and the equipment at each end combines, or “bonds”, them into a single Ethernet connection. From the exchange, your traffic travels over the provider’s fibre network.
Because the copper runs all the way to the exchange rather than to a nearby street cabinet, distance matters a great deal. The IEEE standard’s long reach copper option is rated at up to about 5.7 Mbps per pair at distances of up to 2.7 km, and speeds fall as the cable gets longer. UK providers generally offer EFM only within roughly 4 to 4.5 km of cable from the exchange.
One major EFM provider quotes a typical installation time of about 25 working days, quicker than a fibre leased line because it uses existing copper. For comparison, our leased line cost guide suggests planning for 30 to 90 working days for a fibre leased line.
How fast is EFM?
Most UK EFM services run from 2 Mbps up to about 35 Mbps, the same in both directions. Some providers cap their EFM product lower, for example at 20 Mbps over two or four pairs. Three things decide what you can get:
- Number of pairs. More bonded pairs means more bandwidth, up to the provider’s maximum, usually eight pairs.
- Distance from the exchange. The further the copper runs, the weaker the signal and the lower the speed.
- Line quality. Older or longer copper, joints and electrical interference all reduce the speed each pair can carry.
Providers often guarantee a speed below the line’s maximum, so check the guaranteed figure in the contract rather than the headline. To see what a given speed means in practice, try our upload and download time calculator.
EFM vs FTTC, full fibre and fibre leased lines
| EFM | FTTC broadband | Full fibre broadband | Fibre leased line | |
|---|---|---|---|---|
| Typical maximum speed | Up to about 35 Mbps | Up to 76 Mbps download | Up to 1,600 Mbps download | 10 Mbps to 10 Gbps |
| Upload speed | Same as download | Much slower than download | Slower than download, for example 115 Mbps on a 1 Gbps service | Same as download |
| Shared with others | Usually not | Yes | Yes | No |
| Service level agreement | Business SLA | Broadband terms | Broadband terms | Business SLA |
| Runs over | Bonded copper pairs to the exchange | Fibre to the cabinet, copper to you | Fibre all the way | Dedicated fibre all the way |
FTTC and full fibre maximum speeds are as quoted by Openreach. Fibre leased line speeds are the range we supply.
EFM vs a fibre leased line
Both give you symmetrical, dedicated bandwidth with a business service level agreement. The difference is headroom. EFM tops out at about 35 Mbps, while a fibre leased line starts at 10 Mbps and can grow to 10 Gbps on the same connection. Ours start from £200 a month plus VAT. For most businesses that need guaranteed bandwidth, a fibre leased line is now the better long-term choice.
EFM vs FTTC and full fibre broadband
FTTC and full fibre are broadband: faster downloads, usually for less money, but shared bandwidth, slower uploads and no business-grade guarantees. If your business mainly downloads and can live with broadband terms, full fibre will usually beat EFM on speed and price. If you depend on uploads, hosted phone calls or a guaranteed fix time, EFM or a fibre leased line gives you more certainty.
Is EFM being switched off?
We have not seen a published national switch-off date for EFM. But EFM depends on two things that are being phased out: Openreach’s copper lines and the local exchanges they connect to.
- Copper is being retired. Openreach stopped selling new analogue phone lines nationally on 5 September 2023, and BT intends to retire the old analogue phone network by 31 January 2027.
- Copper sales stop exchange by exchange. Under Ofcom’s copper retirement rules, once full fibre reaches more than 75% of premises in an exchange area, Openreach can stop selling copper-based services there, with a year’s notice to providers.
- Exchanges are closing. Openreach plans to close around 4,600 of its roughly 5,600 exchanges, starting with 105 sites due to be completed by around 2030/31.
EFM equipment sits in the local exchange, so as copper is withdrawn and exchanges close, EFM services will have to move. The practical advice is the same whatever the exact timing: if your business relies on EFM, plan your move to fibre now, while you can choose the timing, rather than waiting for a notice.
If you also have phone lines or alarm and payment lines on the old copper network, our guide to the 2027 switch-off covers what needs to move.
Is EFM still worth it?
EFM can still make sense in a few situations:
- Full fibre is not yet available at your address and a fibre leased line would need significant building work.
- You need symmetrical bandwidth and a business service level agreement now, and modest speeds are enough.
- You want a second, separate connection as a backup alongside fibre.
If none of these apply, a fibre leased line or full fibre will usually give you more speed for the money and a connection that will not need replacing as copper is retired. For a backup line that does not rely on copper at all, 4G and 5G business mobile broadband is another option.
If you have an EFM line now
- Find your contract end date and any notice period, so you can plan a move without paying to leave early.
- Check what is available at your address. Full fibre coverage has grown quickly, so it is worth checking again even if it was not available last time.
- Look at your usage. If cloud backups, video calls or file uploads are slow, you have probably outgrown EFM already.
- Ask your provider whether your exchange is in a stop sell area or on the closure list.
- Allow time for a fibre install. A fibre leased line can take several months, so start well before your EFM contract ends.
Our team in Arundel and Chichester can check what is available at your premises and give you a straight answer on whether full fibre, a leased line or business broadband is the right replacement. We have supported businesses since 2015 and manage the carrier for you.
Frequently asked questions
What does EFM stand for?
EFM stands for Ethernet in the First Mile, often shortened to Ethernet First Mile. It comes from the IEEE 802.3ah standard approved in 2004, which defined ways to run Ethernet over the connection between a telecoms network and a customer’s premises, including over ordinary copper telephone pairs.
Is EFM a leased line?
EFM is often sold as a copper leased line. Like a fibre leased line it gives you the same speed up and down, is usually uncontended and comes with a business service level agreement. The difference is that it runs over bonded copper telephone pairs rather than a dedicated fibre, so speeds are much lower, typically up to about 35 Mbps.
How fast is EFM?
Most UK EFM services offer between 2 Mbps and about 35 Mbps, the same in both directions. The speed you can get depends on how many copper pairs are bonded, usually two to eight, and how far your premises are from the telephone exchange.
How far from the exchange can you get EFM?
Providers generally limit EFM to premises within roughly 4 to 4.5 km of cable from the exchange, and speeds drop as the distance grows. The cable route is often longer than the straight line distance, so an availability check at your address is the only reliable answer.
Is EFM being switched off?
We have not seen a published national switch-off date for EFM. However, EFM runs over the copper network that Openreach is retiring, and Openreach plans to close around 4,600 of its roughly 5,600 exchanges, starting with 105 sites due to be completed by around 2030/31. Businesses on EFM should plan their move to fibre rather than wait for a deadline.
What is the difference between EFM and FTTC?
FTTC is shared fibre broadband to the street cabinet, with copper for the last stretch. It offers faster downloads, up to 76 Mbps according to Openreach, but much slower uploads and no business-grade guarantees. EFM gives a lower but symmetrical, usually uncontended speed with a business service level agreement.
Sources
- Ethernet in the first mile (IEEE 802.3ah), overview of the standard
- Openreach: fibre broadband, FTTC and full fibre speeds
- Openreach: retiring the copper network
- Ofcom: copper retirement second threshold statement, 9 September 2026
- The Register: Openreach copper stop sell, October 2024
- ISPreview: Openreach exchange closures, February 2025
- Published specifications from UK EFM providers, for speeds, pairs, distances and installation times
Speeds, distances and availability vary by provider and address. This guide reflects what we found in October 2026.
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