From the first talkie, The Jazz Singer, to the Humphrey Bogart classic Casablanca, Warner Bros has produced some of cinema’s greatest masterpieces. Now the Hollywood giant is planning an ambitious expansion of its UK studio, giving a huge boost to film-making on this side of the Atlantic.
It is to invest tens of millions of pounds in its studios at Leavesden in Hertfordshire, on top of £150m that it has spent so far on the sprawling, 200-acre site. It was there that Warner Bros turned out the eight Harry Potter films, one of the most successful franchises in the history of cinema, with combined box-office takings of more than $7.7bn.
A master plan for the next 10 years, submitted with its planning application last week, would enable Leavesden to extend its facilities by a quarter.
Warner Bros wants to enable the production at Leavesden of franchise movies and “high-end” television dramas that may need a base over several years, as well as independent films. Expanding the facilities would allow two or three extra blockbusters to be made there every year.
These bigger-budget productions require large sound stages and extensive support facilities. Plans include a “significant expansion” of its Harry Potter studio tour, also at Leavesden, which features a model of Hogwarts castle among actual sets, props and costumes from the films.
Since its 2012 opening, it has attracted more than 5 million visitors, with “more people visiting [it than] Edinburgh castle, London Zoo or Stonehenge”, according to the studios’ economic and social assessment report.
Warner Bros’ vision could give a major boost to employment and training in the UK. Some of the biggest productions employ anything up to 750 people on construction, with an average shooting crew of 250.

Leavesden was a second world war aircraft production base for the Mosquito fighter and Halifax bomber. Rolls-Royce later acquired the site, but left in the early 1990s. In 1994 the James Bond film GoldenEye was filmed there, hangars were converted into sound stages and other productions followed. Warner Bros leased it in 1999 for the first Potter film, before acquiring it in 2010.
Since then, an investment programme has upgraded facilities with state-of-the-art technology. It has an exterior water tank area the size of two football pitches, one of the biggest in Europe.
But, apart from the Potter tour, unsuspecting visitors to Leavesden would never guess that this was a site for film-making. From the outside, you see unprepossessing, functional buildings, rows of rundown marquees and areas of wasteland. When the Observer was given an exclusive tour on a rainy day last week, the site initially looked rather sorry for itself.
But, as we drove around in a golf buggy, suddenly an extraordinary medieval castle came into view in the distance. It was Camelot, built for Knights of the Roundtable: King Arthur, Guy Ritchie’s film starring Charlie Hunnam and Jude Law, which had just completed shooting. It looked real. Moments later, we spotted an enormous classical arch, designed for the latest JK Rowling film, Fantastic Beasts and Where to Find Them, starring Oscar-winner Eddie Redmayne and shooting until January.
A giant waterfall in a jungle was created for the forthcoming Tarzan, starring Alexander Skarsgård, spread over a 100-acre site. One insider said of the backlot: “We think it’s the biggest in Europe. Some of the producers say it’s the biggest they’ve come across.”
Leavesden accommodates both Warner Bros films and major features from other companies, such as Paramount Pictures’s Mission Impossible: Rogue Nation, starring Tom Cruise. The next Bourne thriller, a Universal film, is in the pipeline.
Plans extend to post-production facilities for picture and sound, and an enormous “business media park”.
Commenting on the redevelopment, Roy Button, managing director of Warner Bros productions, said: “Our expansion is amazing. It just means that from ‘fantastic’, it gets to ‘unbelievably fantastic’. Our future is a testament to our past.”