Will BT tell my former ISP I have left/am leaving?

[LetItLoad]

I was of the mind that BT tells my previous Internet provider that I am leaving. Is this actually the case, or do I have to do all the legwork to manually shut everything down with my former provider? I am still getting billed by them. 

[imjolly]

if you use the openreach connection for your internet and take out a new contract with BT then BT should automatically advise your existing ISP that they are now taking over your phone line and becoming a BT customer

[iniltous]

BT serve your notice to the old provider , assuming both providers are using Openreach network and the correct gaining provider led migration process is used, if ( for example ) you moved to BT from a company that doesn’t use Openreach, then you probably should advise that company yourself, otherwise they will continue to provide service and bill you for it.

[Keith_Beddoe]

@LetItLoad 

Bear in mind that if you have  Openreach "fibre" broadband (FTTC), you will lose your existing connection, and if the cabinet is full, then you may end up with a basic broadband connection.