Talk Talk - landline/broadband scam?

[havoc]

Just had someone claiming to be from Carphone Warehouse (but with a TalkTalk ID - I assume they're the same group now) doorstep me and give me some oblique but clearly hard-sell about "upgrade to the telephone server in our area", "have I received a yellow leaflet in the last couple of weeks", and "probably entitled to free broadband now, but I have to come in and check the line!". Of course he "had to do it today if I wanted the free broadband, as they've been round my area already"!

Chap was very evasive when it came to anything other than his script, managed not to answer any specific questions or provide any paperwork, and generally gave me the distinct impression there was a big fat 'catch' to all this that he was desperately trying not to think about in case I was a mind-reader.

Needless to say after giving him a Paxman-esque grilling I gave up and shut the door on him mid-stream...but the whole thing has piqued my interest a little...



So...what's going on, and has anyone else had this?

(My guess is they can do or find-out something relating to the main junction-box inside the house that will enable them to transfer our line to their account (the missing step being them requiring my signature "for the free broadband". Which of course is dodgier than a 3-bob note!)