Enable iPhone Voicemail Divert I have an iPhone 4 running iOs 6.1.3.

I have just switched from O2-UK to T-Mobile.

O2 supported Visual Voicemail and T-Mobile does not (at present)

I have set up my voicemail by dialling 222.

However, I want to set up the diverts (no answer, unreachable, busy) to voicemail but cannot find an option for this anywhere in the Settings app.

How do I switch these on?
After some further googling I have sorted this now. It appears that all UK T-Mobile users get an individual Voicemail divert number. Dialling 222 for the first time should have set this up for me but it didn't.

This worked for me:


I completely reset all divert options by dialing ##004#
I then re-dialled 222 and a message said that number had been set up and I need to reboot the phone. 
I also got an SMS with my voicemail divert number in it.
I rebooted my phone and sent **004*+[the number from my sms]#


My voicemail is now working as expected!