Since the migration of VM’s landline service from PSTN to VoIP, conditional call diversion (busy / no reply) is no longer formally documented or guaranteed on VM’s website. The only call divert feature that’s consistently documented and supported is divert all calls (*21). As a result, the legacy codes *61 / *67 / *76 may still work, but behaviour can vary depending on how the line is provisioned. To clarify, here’s a rewritten version of Muhammod_I’s post:
Divert on Busy
Try this:
*67*07700123456#
If you hear a “number not recognised” or error tone, try:
*76*07700123456#
VM's VoIP lines can respond to either code depending on provisioning. You should hear a confirmation tone if the divert is accepted. To cancel, dial:
#67# or #76# (using the same code that worked).
Divert on No Reply
This uses the standard UK “no reply” divert code (also used on BT) and often still works on VM VoIP. To divert unanswered calls (typically after around 15 seconds):
*61*07700123456#
To cancel:
#61#
Note on ring time
On many VoIP systems, the *61 divert can include a ring-time parameter. On VM, this usually defaults to around 15 seconds. You can try for, say 30 seconds. For example:
*61*07700123456*30#
However, this isn’t documented by VM and may be ignored or overridden by the network, so results can vary.