Kingdom of Heaven was a hard film to make. Directed by Ridley Scott and starring Orlando Bloom, Eva Green, Liam Neeson and Jeremy Irons, it was another enormous historical production, filmed across Morocco and Spain.

A large part of my memories are of Morocco and just how unforgiving the conditions could be. We were working through extreme heat, vicious sandstorms and very long days, often in completely exposed locations while trying to coordinate enormous battle sequences. This was hard graft in hard circumstances.

And the scale of the Special Effects work matched the conditions.

The Siege of Jerusalem was immense. Three full-size siege towers were constructed for the production, and we had these enormous structures burning, under attack and eventually collapsing as the battle developed. Seeing something of that size coming down practically, surrounded by hundreds of performers, smoke, fire and debris, was quite something.

Then there were the trebuchets. These weren't little background props — they were huge pieces of engineering, with throwing arms around 56 feet long. We had enormous flaming projectiles travelling through the air and smashing into the walls of Jerusalem, fire erupting across the battlements and multiple effects running simultaneously across the battlefield.

The whole siege was a mixture of siege towers, trebuchets, projectile effects, huge fireballs, practical fire, smoke, destruction and battlefield atmosphere, all layered together with hundreds of performers and stunt action. Ridley always liked to get as much as possible happening for real in front of his cameras, and on this sequence there was certainly plenty for him to shoot.

When everything was running, it was spectacular — enormous siege engines advancing on Jerusalem, towers burning and collapsing, fireballs crossing the sky and the whole battlefield disappearing into smoke and dust.

It was exhausting work. The heat, sand, wind and sheer length of the days made it one of the tougher location shoots I remember, but when you look at the finished battle, you can see where all that effort went.

Kingdom of Heaven wasn't an easy one — but in terms of sheer scale and old-school practical filmmaking, there aren't many productions quite like it.