A  double decker bus dramatically explodes in the heart of London – but it is all for a movie.

Londoners were left confused as they saw the bus go up in flames as it drove along Lambeth Bridge in central London on Sunday.

Signs had been put in place alerting residents the bridge would be closed between the hours of 8am and 12pm, with Transport for London also confirming the closure “due to filming”.

In a notice warning residents about it, film producers described the film as a “gritty action thriller”.

It is directed by Martin Campbell, who was behind James Bond films Casino Royale and GoldenEye.

The notice, posted on Twitter, stated: “The explosion is controlled and operated by our special effects team.”

It added: “Every precaution will be taken to ensure the safety of the people in the area.”

Following the filming, London Fire Brigade reassured residents the explosion was in fact a stunt for a scene in new action flick The Foreigner, starring Jackie Chan and Pierce Brosnan.

Yet despite the warnings, many people attacked the decision to stage the stunt in the capital given the history of London’s 7/7 terror attacks.