- Relay UK is the national relay service operated by BT to let deaf, hard-of-hearing and speech-impaired people use the telephone with the help of a relay assistant.
- From a textphone or landline, a user reaches the service by dialling the prefix 18001 before the number they want to call.
- The Relay UK app for smartphone, tablet and computer is free to download, and there is no charge for the relay function itself.
- Ofcom's General Conditions require all UK communications providers to give customers access to an approved relay service.
- Emergency calls can be made through Relay UK by dialling 18000 to reach 999, providing a text route to the emergency services.
Relay UK is a free national service where a relay assistant voices a deaf user's typed words and types back spoken replies. From a landline, dial 18001 before the number. Every UK provider must support it.
Last reviewed: June 2026
What Relay UK Is
Relay UK is the national telephone relay service that allows people who are deaf, hard of hearing, deafblind or who have a speech impairment to make and receive phone calls. It is operated by BT under a universal service obligation overseen by Ofcom, which means it exists as a national resource regardless of which provider a customer pays for their line. The service replaced the older Text Relay system and brought relay access to apps as well as traditional textphones.
The principle behind the service is a human relay assistant who sits in the middle of the conversation. The deaf or speech-impaired user types their words, and the relay assistant reads them aloud to the hearing person. When the hearing person replies, the assistant types those words so they appear on the user's screen. The assistant relays the conversation faithfully and does not join in, comment or change what is said.
That neutrality is central to how the service is trusted. Relay assistants are bound by confidentiality and convey what each party says exactly, including tone where it matters, without offering opinions or summarising on the caller's behalf. The effect is that the deaf or speech-impaired person remains in full control of their own call, conducting their own banking, medical appointments or everyday conversations rather than relying on a friend or relative to speak for them. Because the obligation to provide relay access is rooted in Ofcom's regulatory framework on accessibility, the service is treated as a permanent national facility rather than an optional extra that a provider might withdraw.
How Relay UK Works
At its heart, Relay UK is a text-to-speech and speech-to-text bridge staffed by trained relay assistants. A user types using the Relay UK app or a textphone, and the assistant voices that text to the person at the other end of the line. The flow runs in both directions in real time, so a typed message becomes spoken words and spoken words become on-screen text. This lets two people who could not otherwise share a call hold a full conversation.
The service supports several modes. A purely text user can type both sides of the exchange. A user who can speak but not hear may choose to talk directly and read the typed replies, a setup sometimes described as hearing-carry-over or voice-carry-over depending on which sense is being supported. The app allows users to pick the combination that suits them, which is a flexibility older standalone textphones could not offer.
In practice the modern app-based version of the service runs the relay over an internet connection rather than the old textphone tones, which makes the typed text faster and more legible and lets a user start a relayed call from a smartphone, tablet or computer wherever they have data or wi-fi. A user can also receive calls through the service, so a hearing contact who knows the routing can reach them. Because the relay assistant types in real time, conversations naturally run a little slower than a fully spoken call, and a short pause while the assistant catches up is normal. Many users find it helps to mention at the start of a call that it is being relayed, so the hearing person understands the rhythm and waits for each part to come through.
Using Relay UK From a Landline
Landline and textphone users do not need an app to reach the service. The table below sets out the main ways to use Relay UK from a landline or textphone, including the prefixes that route a call through a relay assistant.
| Action | What to dial | Purpose |
|---|---|---|
| Make a relay call from a textphone | 18001 then the number | Routes the call via a relay assistant |
| Hearing person calls a textphone user | 18002 then the number | Reaches a textphone via the relay |
| Contact emergency services | 18000 | Text route to 999 |
| Use the app instead of hardware | Relay UK app | Type calls from a phone or computer |
What Relay UK Costs
The relay function itself is free. There is no subscription to use Relay UK, and the app is free to download. What a user pays is the normal cost of the call to the number they are dialling, charged by their own communications provider in the same way any other call would be. Because a relayed conversation takes longer than a spoken one, regulation aims to make sure disabled users are not left worse off overall, and providers may apply arrangements that recognise the extra time relay calls take.
This is an important distinction. The service that bridges the conversation does not add a fee, but the underlying connection is a standard chargeable call. Users who want to understand exactly how their calls are billed should check the call tariff published by their own provider, since charges for calls to mobiles, premium numbers and international destinations vary between operators.
Why Every Provider Must Support It
Ofcom's General Conditions of Entitlement place a clear duty on communications providers to give deaf, hard-of-hearing and speech-impaired customers access to an approved relay service. This is part of the regulator's wider framework on accessibility and assistance for disabled customers. The effect is that access to Relay UK does not depend on choosing a particular company; the obligation applies across the market.
Providers are also expected to publish accessible information so customers know the service exists and how to use it. As the United Kingdom migrates from the analogue network to all-IP telephony by 2027, the app-based and IP-friendly design of Relay UK is intended to keep relay access working through the transition. Customers who still rely on textphone hardware should speak to their provider about how the move to a digital line affects their equipment.
Relay UK and the Move to Digital Lines
The shift from the analogue network to all-IP telephony, which Openreach expects to complete in 2027, matters for relay users in two ways. The reassuring part is that the modern Relay UK app is built to run over an internet connection, so for anyone already using the app on a smartphone, tablet or computer the switchover changes little: the relay continues to work as it does today, and may even feel more responsive on a digital line. The part that needs attention is older textphone hardware, the dedicated devices with a small screen and keyboard that some long-standing users still rely on, because these were designed around the analogue line and may behave differently once a line becomes a digital voice service.
For that reason, a textphone user planning for the switchover should treat their device like any other piece of equipment connected to the old line and raise it with their provider in advance. The provider can confirm whether the existing textphone will continue to work, suggest the app as an alternative, or arrange suitable support, and a customer with additional needs can ask for this to be handled with the extra care Ofcom expects. Checking early avoids a gap in access at the moment the line moves, and it keeps the route to emergency services through 18000 available without interruption.
Frequently Asked Questions
What is Relay UK?
Relay UK is the national relay service that helps deaf, hard-of-hearing and speech-impaired people make and receive phone calls. A relay assistant reads aloud what the user types and types back what the other person says, conveying the conversation faithfully and confidentially. It is run by BT under an Ofcom universal service obligation and can be used through an app or a textphone.
How do I use Relay UK from a landline?
From a textphone or landline you dial the prefix 18001 followed by the number you want to call, which routes the call through a relay assistant. A hearing person calling a textphone user dials 18002 before the number. Alternatively, the free Relay UK app lets users type calls from a smartphone, tablet or computer wherever they have an internet connection.
Is Relay UK free to use?
The relay service itself is free and the app costs nothing to download. Users still pay the normal cost of the call they are making, billed by their own provider as any other call would be. Regulation aims to ensure disabled users are not disadvantaged overall by the extra time relay calls take, so it is worth checking the call tariff published by your own provider.
Do all UK telecoms providers support Relay UK?
Yes. Ofcom's General Conditions require every UK communications provider to give customers access to an approved relay service. This means relay access does not depend on which company a customer chooses for their line. Providers must also make accessible information available about how to reach the service, so customers can find out how to use it whoever they pay for their line.
Can I use Relay UK to call emergency services?
Yes. Dialling 18000 connects to the 999 emergency services through Relay UK, giving a text route for people who cannot make a spoken emergency call. A relay assistant passes the information between the caller and the emergency operator. Registering a mobile for emergency SMS is an additional option some users set up in advance, and the 18000 route should remain available after a line moves to digital.
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