I have signed up with BT for Call Diversion, to divert calls from my landline to my mobile.

[davidn1]

Trouble is, although they are billing me £6.36pm for this service, they have never actually told me how to set it up! When I phoned them I was told to dial *21*<mobile number> "enter"(?) but this does not work! Can someone please tell me how to set this up? I'm sure it must be easy, the instruction I was given is simply wrong.

[rbz5416 · Accepted solution]

You terminate the divert string with a hash (#).

https://www.bt.com/help/landline/calling-features-and-security/all-about-call-diversion

[chrisjp]

This is indeed a simple process but surely it has significant security implications.
Anyone who has access to your "landline" phone (eg a tradesman doing work in your house, or even a burglar) could easily divert your calls to their mobile phone. They can then receive bank security codes meant for you on their mobile, which could allow them to access your bank accounts.
Surely BT should only allow call diversion with at least the input of your normal BT password?

[davidn1]

Good point, perhaps someone should suggest this to BT. Of course they do have the perfect security for the service already in that they make it practically impossible to actually find out how to use it! I searched MyBT in vain for days to find the answer you gave me.

[iniltous]

TBH , it’s not difficult to find ,
https://www.bt.com/help/landline/calling-features-and-security/all-about-call-diversion
To divert all calls dial: *21*(phone number you want to divert to)#

As far as being insecure, if a burglar has access to your landline to divert the line to themselves, then your security is already compromised, and if they are sat by your landline, then what’s the point of diverting it , they could simply answer the phone ….there is a post someone  was unaware a scammer had reported their landline as faulty , and used to option to have a faulty line put on divert ( obviously useful when legitimately used ) to try and scam access to a bank account, and although it’s a valid complaint, the banks are complicit, in that they chose to use ‘telephony’ as a way to authenticate access , presumably without considering the potential for abuse…perhaps with  this type of authentication it should only be via a mobile number , not landlines .