In reply to a post by RobertoS:

Do people moving networks always take their number with them, or can that come to a halt after the first move?

I have looked into mobile phone number portability and you apply to your current mobile phone network operator for a PAC (Port Authorisation Code). With this code you can keep and transfer your number to a new network operator. Good aye!

http://en.wikipedia.org/wiki/PAC_code

http://shop.orange.co.uk/shop/help/keep

http://support.t-mobile.co.uk/help-and-support/index...

I know how it works when you move from the originating network. But at one time it was certainly doubtful that you could then move it to a third network or even back to the originator. The point being that the number isn't in the later holder's range so may not be transferable.

I was asking about the current position on that .

Compare with landline where so far as I know even BT don't guarantee number retention on a Return to Donor.