Losing BT number - surely not?

[#1]

Just had this e-mail from my 81 year old mother - who I have persuaded not to go with Talk Talk, but to go with plusnet Talk anytime - "I am very concerned as I have just had a letter from B.T saying I will lose my number, wonder if that really is the case, I know Talk Talk said it wasn't and as you know it is the last thing I want to happen'
I told her that plusnet was owned by BT and this won't happen - please re-assure her (and me) that all will be well.

[#2]

How far did the talktalk order get? You shouldn't lose your number if you move to us. Could you PM me the username of the account in question so I can have a look for you?

[#3]

Knowing Talk Talk you could be in bother here!

[#4]

Hi Matt - I e-mailed you the details you asked for yesterday - did they arrive ok?
Mum read me out the sentence in question last night - and it did sound as if she could lose her number. The talktalk was only an enquiry- it went no further
Thanks
Sara

[#5]

Talk Talk salesmen have a reputation for grabbing your line even if it was just an enquiry - if you give them enough details they may just do it irrespective of whether you agreed or signed anything.

[#6]

But all mum's elderly friends who've been persuaded to switch to Talk Talk and tried to persuade her too - hence the enquiry - HAVE kept their numbers - are you saying Plusnet can't manage the same? And I thought BT owned plusnet. Very worrying (and puzzling)

[#7]

Hi there,
If TalkTalk didn't actually get hold of the line then everything will be fine and the number will be retained.
Problems can occur if the transfer to Talk Talk completes (or part of it does), as the number is then classed as a Talk Talk number and not a BT one, so any BT based provider (such as us) would not be able to reclaim that number without requesting it back from Talk Talk.
It doesn't sound like this has happened in this case though (as a letter was received from BT) so it should be just fine.