Watford is to become the unlikely new home for Batman and Superman after Warner Bros confirmed that it is to go ahead with a huge expansion of its Leavesden film studios.

The addition of ten new sound stages and 400,000 sq ft of production and support space will increase the filming capacity of the studios, where the Harry Potter films were shot, by 50 per cent.

Warners expects its investment to create 4,000 jobs directly and indirectly and contribute an extra £200 million each year to the UK economy. Building work is due to begin next spring and complete in 2027, after which Leavesden will become the main production hub for DC Studios, the Warners arm responsible for making the Superman, Batman and Wonder Woman films.

Jeremy Hunt, the chancellor, said: “Warner Bros Discovery’s ambitious plan to grow its Leavesden studio . . . means that British-made entertainment will continue to delight and entertain global audiences.” Hunt was in Los Angeles yesterday, meeting David Zaslav, chief executive of Warner Bros.

The expansion, planning permission for which was granted by Three Rivers district council and Watford borough council earlier this year, will cap the dramatic transformation of a site that in the mid-1990s was a disused airfield. The aircraft hangars and factories were first turned into filming space for the Bond film GoldenEye. Since then, a host of shows and movies have been filmed at Leavesden, including House of the Dragon, the Game of Thrones spin-off series, and, most recently, Barbie.

The UK has established itself as a filming hub for big production houses by offering generous tax breaks. Disney is reported to have earned upwards of £300 million in rebates for filming its Star Wars sequels in Britain.

Property investors more used to financing offices, flats and warehouses have been looking to add film studios to their portfolios to take advantage of the production boom.