What did you make of the season finale?
"I was really pleased with it, because it's the closest we've come to season one in terms of the standard of excellence. They needed to get it back on track and they have."
You were quite critical of season three, weren't you?
"So was everyone else, as far as I know. I'm not alone in that. It's difficult not to feel proprietorial towards the work. When you feel a drop in quality, it would be dishonest to yourself if you didn't acknowledge that."
What do you think the problems were?
"The writing. We all know what the executive producers, Damon [Lindelof] and Carlton [Cuse], were going through because they had this burden of an endless show. I don't think it's what Damon wanted in the first place. He always used to say to me 'Wouldn't it be great if we were a bit like the Sex Pistols and did just one season of great television and then bang, that's it?' Sort of smash and grab. Obviously you can't do that on primetime network TV but he wanted a limit to the show. He managed to do a deal where he was able to achieve that. Now that we have an ending to aim towards, I think it's inevitable the quality will get better."
What would have been your ideal number of seasons?
"Ideally, five, for me. Five or six. Actually it does work out to five because we've got shorter seasons now."
What have you learned from doing Lost? You seem to have found it a bit of a burden...
"That's an interesting word we keep returning to. 'The burden of writing'..."
'The burden of Lost.'
"Come on, it's not a ****ing burden. You're being paid, obviously - I don't ever remember being paid in England, even though the quality was there with things like The Buddha of Suburbia. I don't think it's a burden being paid, but it's a real discipline to play the same character over years rather than months or weeks. It requires a certain amount of stamina."
There are two seasons to go but each has fewer episodes. What does that mean for you, production-wise?
"It's a shame because we've been ****ed by the strike. We have an impending one and we had the one with the writers, which came right in the middle of the season and meant we had a few months off and had to go back to work. It ****ed up our hiatus. The whole thing was like 'oh, you just have to do six months in Hawaii instead of ten, then you can have the other six months to do films.' Well it didn't work out that way, did it? It looks like it won't work out again."
What did you make of the flash-forwards this season?
"I thought it was a bonus, for me personally. It's a challenge to be able to play a character in the present and then zoom ahead to a point when they may have undergone great changes. I felt in season four, Sayid was spiritually dead [in the future], and something awful happened to his soul. To be able to play that and then go back to the island, where he's still quite active in life, was good."
How much are you told about the character, doing these future scenes?
"Absolutely **** all."
Then how do you prepa..
"****** only knows. I was talking to Jorge [Garcia, Hurley] about that yesterday. I was saying 'I got my script a week and a half before we shot' and he said 'I got mine three days before we shot it'."
So you get no guidance on how Future Sayid is feeling?
"Absolutely not. I don't know if this is a good thing or not, but at this point, the writers feel they can trust us with whatever we're going to do with it."
As a viewer of the show, which I assume you are...
"No, I'm not. I only saw the pilot. But anyway, go ahead."
...which of the many twists do you want to find out the answer to?
"The foot with the ****ing toe missing. What was that and is it going to come back? Is there going to be two feet next time, with a geezer on top as the rest of the body?"
What do you make of Harold Perrineau's comments last week suggesting that race played a part in his exit?
"I was very pleased to see Harold back and very disappointed that it didn't continue. But I can't comment until I've read what he said - or if I'm honest, until I've spoken to Harold and heard what he says he ****ing said!"
When we last spoke you said you knew how the show would end, "geographically" speaking.
"Yeah, the island. I still presume it's going to be the island. I think season five's going to be Matthew [Fox, Jack] rounding up us lot to go back to the island, or whoever he can get to go back - maybe some people don't, because they can't be ****ing bothered - and they go back and then there's this big kind of conflagration on the island. Will good triumph over evil? I don't know. It's just a rough idea."
So you know nothing solid about the future seasons, then?
"It's been like this from day one. They've never told us anything."
Do you want to know?
"At first, yeah. It's like your spiritual development. You're like three steps forward, five steps back. You'd think after four years you'd be used to being kept in the dark but every now and then you do get frustrated and think 'come on, for ****'s sake, tell us something!'"
Once Lost is done, would you do a network series again?
"To be honest with you, I think you've got to go where the good writing is, whether it's film or TV. There's a lot of crap films around at the moment. So to answer the question, wherever the good writing is."
Would you be open to the possibility of doing a spinoff of Lost?
"I can't believe they would do that. If they did it would be hilarious. Maybe it could be Locke... and Ben... and a baby! You know what I mean? Come on!"
So that's a 'no' then.
"I just don't think it'll ever happen. It's a preposterous question. If it happens then Damon should be shot!"
Lost returns in February 2009.