If NTL are actually providing an "up to" 10Mbit service - they should advertise it as such. As per
http://www.home.ntl.com/page/broadband3 it's "10Mbit broadband", not "upto" or "near to".
As far as i'm aware, it is mainly ADSL connections that provide "up to" services. This is due, in part, to the nature of the *dsl technology, in that it deteriorates heavily over long cable distances. ISPs are therefore required to state that they are "up to" connections, because each individial line will sync at a speed dependant on their distance from the exchange.
Cable is different. Due to the way it is brought into the users home - everyone should be able to connect at 10mbit speeds, assuming they have the correct hardware.