[graf_von_anonym]

I'm curious as to what remedy the original poster seeks.

I think there's still a question here as to the actual issue. Admittedly, it's late, and while it may have been explicitly stated I'm not sure as to whether it's "variation within contract" or "implementation of STM" that's the core problem.

In terms of contract law I'm sure that variation within terms and conditions has been tested in the courts before, probably most recently in general terms with regards to bank charges, but I'd wager there's precedent for "unilateral" variation within ancillary documents upon which contract is effectively predicated, wherein provision of services (in this case) is constrained by a subsidiary agreement.

In terms of STM, I do agree that there are other regimes which could be adopted, but for the most part the Virgin system does fulfil its objectives. The issue could be drawn with those objectives, which is to say that the seemingly punitive aspect of it is somewhat harsh. Though it is enough to say that peak usage in peak times can affect other customers negatively, so throttling a connection until outwith peak times will have a negative effect on one user and a positive effect on others. Virgin can only attempt to keep as many customers happy as possible. I can state with some confidence that no ISP in the world* can provide its full stated line speed to all of its customers simultaneously, and Virgin Media's policies are designed to accomodate usage on that basis.

I'm also curious as to what other remedy the original poster has sought. I trust, though I cannot be sure, that before resorting to the courts in what I assume to be a civil action he sought redress through Virgin's own complaint process, then, with specific reference to contractual terms through OFCOM or some other ombudsman? If not then I fear that Virgin's argument may be that his dispute itself falls outwith his contract, as he did not follow provisions therein for dispute resolution.

Of course, I'm secretly Richard Branson.

* With some provision for variation where what is provided is a leased line or similar trunking level connection. No consumer ISP would be more accurate, but even then most business providers don't. In fact, I would hazard a guess that there simply isn't enough internet for all internet users to use their connection to maximum.