I'm interested in the evidence you have to support that. Has a study ever been done? (I'm not trying to call you out; I'm legitimately interested in reading it).
Well, there is evidence I'm sure but I don't have a list of references
Normal sleep goes through cycles. In the deepest state of sleep it is very difficult to raise someone when they are in this cycle. In the other cycles, small disturbances will certainly wake someone up. In order for the subject to be asleep and not wake up he would need to be in deep sleep. He can not have been in this state for 13hrs. Basically, the guy couldn't have been asleep.
We can also rule out coma. People in comas don't look like they do in films, dramas. They can move and open their eyes, etc. It is a brain state. No-one 'wakes up' and starts asking where they are. No-one is suggesting he was in a coma, so we don't even need to consider it.
Keeping someone anesthetized is very dangerous and would require the constant attention of an anesthetist (who would refuse to do it). We can obviously rule this out.
The only thing left is hypnotism. The type of hypnotism needed to keep someone in the state the guy was in the programme... well Derren Brown has previously stated that it doesn't exist and I believe him.
We have all seen people hypnotised on stage. Graham Norton had some pretending to be dogs on a recent show. What Derren Brown did - and how he did it - is exactly the same as that. All stage hypnotist's need suitable subjects for stagework, all Derren Brown had to do was find someone who would be suitable for a long and extended version of the same kind of thing.
The Daily Mirror could follow them all they liked and not find anything that would prove it was fake. In the same way they couldn't do so in a regular stage hypnotist show.