Terms and conditions are very much legally binding in the case we are discussing (online sales) - you are explicitly offered them as the contractual terms of sale.
What T&C can't do is rescind the basic consumer rights offered under law
electromagnetic contends that the "basic consumer rights offered under law" include the obligation for the seller to have an infinite number of any item in stock and ready to ship at whatever price the website happens to say, even if it's an obvious mistake.
Well I've just been skimming the books on my law shelf (Google was completely unhelpful) and they seem to back up what we've been saying so far; there is no provision under current consumer law to force the retailer into honouring it (actually there is sort of one but it's wording basically says "unless the retailer says otherwise..." etc.)
