'Ripped'
I do understand your frustration, but what I
can't understand is why you don't do something about it?
Surely where you live in London you get get ADSL? Why don't you just ring BT, give them your ntl account number/phone number etc (should take less time than it takes to make a post on here), then once they have confirmed they can port you number, sit back & relax in the knowledge that you will soon be surfing via xDSL.
The world is your oyster when it comes to DSL ISPs (I'm sure you know my thoughts on Pipex

)
FYI-Ben has just switched from ntl to BT, the phone call took approx 10 mins, they agreed to port his number, & offered him a date
& a time that they would arrive to do the work (about 10 days from phone call to said date from memory), as soon as he has his BT line, he will be choosing a DSL ISP.
I really don't know what is stopping you doing the same thing...