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United Kingdom · Clinic SetupSeptember 19, 20264 min read

Call Diversion for UK Clinics: BT and Mobile Codes Explained

How UK clinics can divert calls when busy, unanswered or closed, with BT landline codes, mobile network codes and tips for cloud phone systems.

Clinic phone set to divert calls in a UK practice

Introduction

Call diversion lets your clinic keep its number while calls you cannot answer go somewhere useful. This guide covers BT landlines, mobile networks and cloud phone systems.

Key takeaways

  • Divert only when busy or unanswered, so reception still answers first.
  • BT landlines use * codes; mobile networks use ** codes.
  • Call Diversion may need switching on, and diverted calls can be charged.
  • Test with a second phone before relying on it.

1. BT landline codes

On most BT lines with Call Diversion switched on, dial these from the clinic phone, replacing [number] with the destination number:

  1. Divert all calls: <strong>*21*[number]#</strong>
  2. Divert when busy: <strong>*67*[number]#</strong>
  3. Divert when not answered: <strong>*61*[number]#</strong>
  4. Cancel divert all: <strong>#21#</strong>

2. Mobile networks (EE, Vodafone, O2, Three)

Mobile networks use the standard GSM codes:

  1. Divert when busy: <strong>**67*[number]#</strong>
  2. Divert when not answered: <strong>**61*[number]#</strong>
  3. Divert when unreachable: <strong>**62*[number]#</strong>
  4. Cancel all diverts: <strong>##002#</strong>

3. Cloud and VoIP phone systems

If your clinic uses a hosted phone system, diversion is usually a setting called ‘call forwarding’, ‘overflow’ or ‘failover’ in the admin portal. You can often set different rules for opening hours and out of hours.

Which diversion rules clinics usually choose

Diverting every call means reception never hears the phone, which is rarely what a clinic wants. A common setup is:

  1. <strong>Opening hours:</strong> divert when busy and when not answered after 20–30 seconds
  2. <strong>Lunch break:</strong> the same rules, so a short-staffed desk is covered
  3. <strong>Evenings, weekends and bank holidays:</strong> divert all calls

Troubleshooting

  1. Code rejected: the line may not have Call Diversion switched on. Ask your provider.
  2. Calls still ring out: check the ring time before a no-answer divert takes effect.
  3. Caller hears a message instead: a voicemail service may be taking the call first. Turn it off or change its timing.

4. Check costs and test

Your provider may charge for diverted calls. Ask before you switch on. Then test by calling from a personal phone while the line is busy and again when nobody answers.

5. Where to divert to

Diverting to Clinic24 means callers are answered in a natural English (UK) voice and booked into your diary. See Clinic24 for UK clinics.

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