DID numbers · GB +44
United Kingdom DID Numbers for inbound and CLI
Local numbers in United Kingdom that ring your SIP endpoint and double as verified outbound caller IDs. Order, document and route them from the portal.
- country_code
- +44 · GB
- national_len
- 10 digits after the trunk 0 (9 for a few legacy areas)
- mobile
- 071–075, 077–079 · 07624 Isle of Man
- fixed
- 01 and 02 geographic (020 London, 0161 Manchester, 0121 Birmingham) · 03 non-geographic, charged like geographic · 0800 / 0808 freephone (domestic only)
- regulator
- Ofcom, with the ICO for direct-marketing enforcement
- timezone
- GMT (UTC+0), BST (UTC+1) in summer.
- reviewed
- 2026-10-30
Overview
DID numbers to United Kingdom
A DID (direct inward dialing) number gives you a real United Kingdom number on your SIP trunk. It receives calls from local customers and, because you hold it, it is also the strongest caller ID you can present on outbound traffic to United Kingdom.
UK geographic numbers in every area code, 03 non-geographic numbers and freephone 0800 numbers are available. UK numbers you hold make the most reliable CLIs for UK traffic.
UK traffic is dominated by customer service, collections and B2B sales. Networks block calls with invalid or non-dialable CLIs, so number hygiene has a direct effect on completion rates.
| Type | E.164 |
|---|---|
| Mobile | +44 7700 90012307700 900123 |
| Fixed | +44 20 7946 0123020 7946 0123 |
| Non-geographic | +44 333 090 01230333 090 0123 |
+44 followed by a 9–10 digit national number; geographic numbers start 01/02, mobiles 07.
Regulation · Ofcom, with the ICO for direct-marketing enforcement
Caller ID rules in United Kingdom
A practical summary for operations teams, not legal advice. Confirm current requirements with counsel before you launch.
Caller-ID presentation
Call authentication
Ofcom CLI guidance
PECR and the TPS
Persistent misuse
Calling hours
No statutory window, but Ofcom’s persistent-misuse policy and industry practice point to 8am–9pm, with care on Sundays.
Dialing & setup
Dialing United Kingdom correctly
- Drop the trunk 0: 020 7946 0123 becomes +44 20 7946 0123. London is 20, not 207.
- Freephone 0800 and 0808 numbers cannot be dialled on international routes.
- Screen against the TPS and CTPS at least every 28 days, as the ICO expects.
- Predictive dialers must play an information message on abandoned calls and keep abandoned rates within Ofcom’s policy.
Caller ID best practice
Use a valid UK geographic or non-geographic number you hold, make sure it is dialable and reaches your organisation, and avoid presenting mobile numbers you have not been allocated.
Troubleshooting
Common SIP errors on United Kingdom calls
- 403
Forbidden
The CLI failed validation: invalid format, unallocated, on the DNO list, or a UK geographic number on international-origin traffic.
- 484
Address Incomplete
A short number, usually because the trunk 0 was stripped twice or a digit was lost in CRM export.
- 404
Not Found
The number is not in service. Ported numbers are rarely the cause on UK routes.
Quality guidance
What healthy United Kingdom traffic looks like
Healthy UK routes show low PDD and stable ACD. A sudden ASR drop with many 403s almost always means the CLI failed validation, not that the route degraded.
40–60%
2.5–4min
2–4s
Typical ranges on healthy routes, as guidance only. Results depend on your lists, CLI reputation and campaign type. Live per-destination stats are in your portal.
Setup
Connect your DID number for United Kingdom
Replace the placeholders in angle brackets with the values from your portal. Full trunk templates for each platform are in the portal after sign-up.
; extensions.conf — inbound United Kingdom DID from CLIRoutes
[from-clirroutes]
exten => +442079460123,1,NoOp(Inbound United Kingdom DID)
same => n,Set(CALLERID(name)=GB support line)
same => n,Goto(ivr-main,s,1)
; Present the same DID on outbound United Kingdom calls once it is verified.FAQ
United Kingdom DID numbers: FAQ
Can’t find what you need? Our routing team answers within the hour, around the clock.
Why are some of my UK calls failing immediately?
UK networks reject calls with invalid or unallocated CLIs. Check the number format in your dialer (E.164, no leading zero after +44) and that the number is allocated to you. Your portal shows failure causes per call.
What abandoned-call rate should my dialer target for the UK?
Ofcom’s policy expects a low abandoned-call rate measured per campaign over 24 hours, with an information message on every abandoned call. Configure your dialer’s drop-rate target conservatively and keep the logs.
Can I present a UK landline number on calls from abroad?
Only on paths where the call is recognised as legitimately originated for a UK customer. UK networks block international-origin calls that present UK geographic CLIs otherwise. We route verified UK-CLI traffic accordingly.
How often must I screen against the TPS?
The ICO expects screening at least every 28 days, and against the CTPS for business numbers. Keep evidence of each screen.
What is the difference between the TPS and CTPS?
The TPS covers individuals and sole traders; the CTPS covers companies and other organisations. Both opt out of unsolicited live sales calls.
What documents do I need for United Kingdom DIDs?
It depends on the number type. Many geographic numbers in United Kingdom require proof of a local address or business registration; toll-free and non-geographic numbers usually need less. The portal lists requirements per number type before you order.
Other products in United Kingdom
Nearby countries
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United Kingdom DID Numbers
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