It was the growth of the Harry Potter franchise that set up the UK film industry to be a world leader in visual effects, Josh Berger, president and MD Warner Bros. Entertainment UK, Ireland and Spain said today during his keynote at MBI’s Creative Week Media Summit.

“As I think it had been discussed pretty broadly during the Gravity campaign, much of that team had worked on Potter. Potter, it’s fair to say, was very important to the growth of the VFX industry in the UK. Some people say it was the thing that propelled the industry here.”

Berger noted that with the first Harry Potter film in 2000, less than 15% of the VFX work was done in the UK. By the final film’s production in 2010, more than 85% of the effects were done in Britain. “There was an expansion of the skill base, the assets, the sheer numbers of people working in the industry.”

It was that base of skills and talent that Warner could again tap into for the groundbreaking Gravity, with London-based Framestore leading the VFX.

“Gravity in a way is a crowing achievement in that period of growth and expansion,” Berger added. “The great thing for our industry here is that those skills are here. With successes like that, companies like Framestore and Double Negative can expand, people can start their own firms — with continued investment, the ecosystem is expanding and growing.”

Warner Bros itself is part of that growth, after acquiring Leavesden Studios. “[Shooting at Leavesden] worked out incredibly well, so much so that we decided to buy it after the Potter series was finished. It might have been better to buy it at the beginning, for example.,” he said with a laugh. “The truth was that it wasn’t in the cards during the production. Once we finished we had a chance to reflect on what we had done and what we’d be doing in the future. It was such a superlative experience that we decided to plant our flag and make it our permanent home and invest for the future. We knew we were committed to making films here.”

He noted that Warner would still be a customer of Pinewood Shepperton, for instance, despite having its own studio here now (although possibly with less volume than before).

“The investment in the market means all boats are rising as the tide rises, I think that’s the right metaphor. Our coming in and investing certainly brings other people to come have a look. The level of production here is substantially up. There is a lot of competition for that space. When Star Wars decides to come here that is a long term hundreds of millions of pounds investment, that is great news no matter where [which studio] it is made.”

The tax credit system is another key to the UK’s current boom, he added. “The tax credit system is very important. This government and the previous government have been incredibly supportive…Tax credits aren’t the reason the industry is doing so well, but without them it would be a very very different story. Some estimates say the production would drop 50% if there were no tax credits.”

The Potter world is set to continue with with Warner’s Fantastic Beasts And Where To Find Them, the first in a spinoff film series based on Newt Scamander’s adventures. The first film in that series, which author JK Rowling is writing, will be set in New York in the 1920s; it will be readied for a November 2016 theatrical launch.

The Media Summit continues today at BAFTA with further speakers including Channel 4 chief executive David Abraham; Vice Media’s Matt Elek, Sky’s Stuart Murphy and Twitter’s Bruce Daisley. MBI, the parent company of Screen, Broadcast and Shots, continues to host Creative Week events including today’s VFX Summit, and tomorrow’s International TV Forum and HD Evolved seminars. More info at www.creativeweek.co.uk