Do Vodafone cancel pre-existing broadband contracts?

[electrodruid]

For my home broadband, I'm moving from BT to Vodafone. When I spoke to BT to cancel my contract with them, they said the best way to do things was simply to start a new contract with Vodafone - once the Vodafone connection is up and running they would automatically contact BT to cancel that contract on my behalf. The thinking was that that way we could be sure that my BT contract wouldn't end before the Vodafone one is up and running so I'd never be without broadband.

My question is: is this true? Does Vodafone do this, or was the BT representative lying and I actually do need to cancel directly with them myself? I didn't see any mention of it during the process of signing up for the Vodafone contract.

[Ripshod]

Yes, Vodafone do do this for you automatically. BT were correct in their advice. 

[Jayach]

Yes, as @Ripshod says it is true, however it isn't just Vodafone, any FTTC to FTTC swap is regulated by Ofcom.

Switching broadband provider - Ofcom

But bear in mind it is only FTTC suppliers, if switching technology FTTC/FTTP/Cable(Virgin) it is up to you to ensure the current broadband is cancelled, it may not happen automatically.