Monty Python And The Holy Grail was Terry Gilliam's first film as a director. Here he remembers how he taught the nation to laugh at castles

Though recently more famous for the films he hasn't made (Watchmen, Don Quixote), Terry Gilliam is finally getting to work on what seems like a goer. Based on Terry Pratchett and Neil Gaiman's comic Good Omens, his next film is an apocalyptic comedy about the Antichrist being lost due to a hospital cock-up. With a healthy budget and "two very major stars" this should mark the return of one of our most original directors. Taking time off from pre-production, Gilliam casts his mind back to his debut, Monty Python And The Holy Grail.

Had you had much directing experience when you took on The Holy Grail?

When I was a cartoonist in New York, a group of friends and I would go out at weekends with a roll of 16mm film and make little skits. You know Harry Shearer (Spinal Tap, The Simpsons)? He's one of my oldest friends - we'd shoot him in the park eating spaghetti or whatever. Also I went to night classes in film-making. One evening a week for four weeks. So yes, I am qualified to direct.

You've had a lot of troubles with studios in the past, did anyone interfere with Holy Grail?

There was no studio interference because there was no studio; none of them would give us any money. This was at the time income tax was running as high as 90%, so we turned to rock stars for finance. Elton John, Pink Floyd, Led Zeppelin, they all had money, they knew our work and we seemed a good tax write-off. Except, of course we weren't. It was like The Producers.

For a cheap, quickly made comedy it still looks fantastic.

Terry and I were big fans of Pasolini; that dirty realistic look, you could almost smell his movies. Add a little smoke and filth to a scene and it starts to look more artistic. What works for me is that it all looks so authentic, though not necessarily accurate, but it's juxtaposed with such downright silliness. We ruined that period for a lot of directors: Bresson's very serious Lancelot Du Lac came out after us - in Paris the audience couldn't stop giggling.

Was it a smooth shoot?

I wouldn't make that film now, I know too much. From the start everything went wrong: immediately before filming started the National Trust cancelled our access to the castles. They said we wouldn't "respect the dignity of the fabric of the buildings"! These places had dungeons and blood on the walls for God's sake! They've stood for hundreds of years against hordes of invaders, what were we going to do? Make people laugh at castles. You know when they see Camelot and say, "It's only a model." Well, it was - a big cut-out.

The Pythons all have strong personalities. Any tantrums?

Oh yes, all of us. These were well-educated, cultured men who didn't take kindly to standing in ditches covered in mud. I had a huge argument with John Cleese while I was trying to shoot a sequence he'd bloody written. I stormed off and quit the movie... for at least two hours. But the arguments were all about quality, despite the personal digs.

How do you think it stands up as a comedy?

I saw Blazing Saddles recently and it seemed so slow but Holy Grail is packed. It was always a series of sketches linked together and we kept tightening and tightening it in the writing. It doesn't outstay its welcome and rather than wind down at the end it just stops abruptly.

· Monty Python And The Holy Grail is out on DVD £19.99, Columbia Tristar