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CLIRoutes

CLI routes · GB +44

United Kingdom CLI Routes with verified caller ID

Deliver your authorised number to United Kingdom on audited carrier paths, with CLI delivery reported per destination code and prepaid crypto billing.

Europe+44
key_facts · gb
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

CLI routes to United Kingdom

A CLI route to United Kingdom is a wholesale path that keeps the caller ID you send intact all the way to the handset. CLIRoutes only places CLI-tier traffic on paths that passed CLI test calls on United Kingdom’s main networks, and removes paths that stop passing.

UK CLI routes are tested against Ofcom-compliant validation on every major network. We keep UK-CLI traffic on paths that are recognised for UK-origin customers, so your geographic or 03 number displays instead of being blocked.

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.

Number formats
TypeE.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.

Last reviewed

Caller-ID presentation

Ofcom General Condition C6 requires the CLI to be a valid, dialable number that identifies the caller and that the caller may use. Networks block calls with invalid CLIs, and since 2023 they block calls from abroad that present UK geographic numbers unless the call is genuinely from a UK customer. Ofcom has consulted on extending this to UK mobile CLIs.

Call authentication

The UK has no STIR/SHAKEN mandate. Ofcom relies on General Condition C6, the Do Not Originate list and international-gateway blocking, and keeps CLI authentication under review.

Ofcom CLI guidance

The CLI must be a valid, dialable UK number that identifies the caller and that the caller has permission to use. Networks are expected to block calls with invalid CLIs.

PECR and the TPS

Marketing calls must not go to numbers registered on the Telephone Preference Service unless the person has specifically consented. Automated marketing calls require prior consent.

Persistent misuse

Ofcom can act against abandoned and silent calls. Predictive dialers must keep abandoned-call rates low and play an information message when a call is abandoned.

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%

ASR

2.5–4min

ACD

2–4s

PDD

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 CLI route 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.

Asterisk dialplan+44
; extensions.conf — United Kingdom (+44) on the CLIRoutes CLI tier
[outbound-gb]
exten => _44X.,1,Set(CALLERID(num)=+<AUTHORISED_CLI>)
 same => n,Dial(PJSIP/<TECH_PREFIX>${EXTEN}@clirroutes,60)
 same => n,Hangup()

; Test with an E.164 number such as +44 7700 900123

FAQ

United Kingdom CLI routes: 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.

Which caller ID can I present on United Kingdom calls?

Only numbers you own or are authorised to use. 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.

Start calling United Kingdom with your real number

Sign up, complete a short business verification and fund your wallet in USDT, BTC or ETH. Your rate deck is available in the portal after sign-up.

United Kingdom CLI Routes

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