From the Rogue One sand storm to the red dust of Maleficent 2, one Yorkshire firm is proving that when it comes to screen-grabbing special effects, films don’t have to rely on CGI.

T here’s not much about the premises of VFX which suggest red carpet glamour. Tucked away on an industrial estate just a couple of miles from the centre of Leeds, it’s an anonymous, concrete sort of place and yet inside these apparently ordinary surrounds is where movie magic is made.

It was here where chemical specialist Steve Foster cooked up the formula for the chocolate river in Tim Burton’s remake of Willy Wonka and the Chocolate Factory. It’s also here where he created the batch of ewes’ milk in which Charlize Theron bathed in Snow White and the Huntsman and where he answered a call from Sacha Baron Cohen’s people politely enquiring if he might be able to rustle up 16,000 litres of fake elephant semen.

“We’ve taken some odd requests over the years, but that has to be the oddest,” says Foster who is clearly not the kind of man easily phased. “It was for his film The Brothers Grimsby and let’s just say when the tanker driver came to collect it, he wasn’t quite sure what to say. I’ll be honest, I never went to see the finished film, but everyone tells me it did the job which is pretty much all I need to know.”

VFX is a side project of the chemical company Vickers Labs, which specialises in the more humdrum business of making contact lens solution and supplying school science laboratories. Foster admits that they never intended to get into the weird world of fake blood, vomit and specialist smoke effects, but a phone call in 2005 changed everything.

“Joss Williams and Mike Dawson were heading up the special effects team on the new Willy Wonka film starring Johnny Depp. They needed fake chocolate and they needed it quickly and someone suggested that we might be able to help.

“We had done a tiny bit of film work before then but that phone call really was our big breakthrough and it was on a scale we could never have imagined.”

It took a little trial and error to get both the right consistency and the correct colour for Willy Wonka’s chocolate, but once the production team gave the nod, Foster headed down to Pinewood Studios for his first real introduction to the British film industry.

“We knew that we could deliver, but until they actually started filming and you could see everyone was happy my heart was in my mouth a little,” he says. “When they initially contacted us it was for a sample of 25 gallons of chocolate. In the end it escalated to 1.25 million gallons and we had to work round the clock to ensure the waterfall kept flowing.

“Working behind the scenes wasn’t exactly glamorous, but it was a real insight into how the film business operated and it paid off because we ended up working with Joss and Mike on both Sleepy Hollow and Sweeney Todd.”

For those next two films it was fake blood rather than chocolate which Steve created from scratch and despite the advance of CGI, which has allowed special effects to be created at the touch of the a button, the calls to VFX have kept on coming.

“Digital technology has obviously had an impact, but a lot of directors prefer something which looks a little more realistic and that’s where we come in,” says Foster, opening the door to a laboratory with walls lined with bottles labelled splatter blood, alien slime and pea green vomit. “Whether you are wanting something which looks like water or Golden Syrup, getting the consistency right is the easy bit. Getting the colour right is much trickier, because it can look so different under the full glare of studio lights.

“It’s true what they say about the film business, it really is who you know. We have never gone out and marketed what we do, but after working on Willy Wonka and the Chocolate Factory our reputation has spread and we are known now as a company who can turn around an order for pretty much anything quickly.”

Now also specialising in smoke effects, it was VFX which supplied the blue flame used in the Hades scenes in the Clash of the Titans reboot and it was Foster who masterminded what he describes as the “various types of black goo” for the television adaptation of the epic poem Beowulf.

“We also worked on the first Snow White and the Huntsman movie,” he says. “The production team needed a tanker full of ewes’ milk for Charlize Theron’s character Queen Ravena to bathe in. That was tricky in the sense it had to be opaque enough to cling to her body, but sill liquid enough to look like milk. We also had to ensure that it could be heated up a little on set so she wasn’t stepping into a bath of something bitterly cold.

“It is a really memorable scene and it’s always nice to think that we have played a part in bringing someone’s vision to life.”

Most recently VFX has finessed the perfect recipe for sand which was used in Rogue One: A Star Wars Story, provided the snake blood which was splashed into Jude Law’s face in King Arthur and the Legend of the Sword and concocted a job lot of red dust for Maleficent 2 starring Angelina Jolie.

“Everything which comes out of our factory can’t just look good, we also have to guarantee that it is completely safe for the cast and crew to work with,” says Steve, who has also produced fake mud used in a Battle of the Somme reenactment in Manchester’s Heaton Park and black vomit which poured out of an over-sized human head in a headline grabbing window display in Selfridges flagship Oxford Street store.

“The latest commission we won was again for fake blood, this time for the new series of the ITV crime drama Vera. We are a small team here, but we have a lot of expertise and whatever the request we are always willing to give it a go.”