Mystery over 4 helicopters circling major landmarks and 'heading towards central London'

London's skies have been buzzing with the sound of four helicopters, drawing the attention of thousands of residents and flight enthusiasts. The choppers took off from Biggin Hill Airport near Bromley at approximately 11.14am on Thursday, captivating thousands of people tracking their movements online.

Sharp observers on Flightradar24 have pinpointed one helicopter, with the registration G-RYFF. It is understood to be privately owned, and over 2,000 individuals have followed its path over London.

The quartet was seen executing circuits around Greenwich Park, tracing the Thames, and circling the City of London before lingering over the Isle of Dogs and near the Cutty Sark. The latest sighting placed the helicopter over New Addington in Croydon, possibly en route back to Biggin Hill.

Curious locals have flocked to social media for explanations, with one user asking: "Why are there so many helicopters over Isle of Dogs/ Cutty Sark? Update: They have all just left and are heading towards central London."

Reddit users have recognised the G-RYFF helicopter from its appearances in the Netflix show 'Gentlemen', a James Bond movie, and an episode of 'Clarkson's Farm'.

This helicopter has become well-known amongst film and TV buffs, with one telling Reddit: "I was watching Gentlemen, by Guy Ritchie on Netflix and the character played by Giancarlo Esposito owns an Augusta registration G-RYFF. The next day I'm watching 3 Body Problem and Mr. Evans, played by Jonathan Pryce owns the same helicopter.

Armchair aviation experts pointed out that the helicopter is operated by a firm called Castle Air, which they called "a big name in private aircraft operation in the UK."

G-RYFF is a twin-engine Agusta A109S Grand helicopter often used for VIP transport. Something it is frequently depicted doing on-screen in Guy Ritchie's upper-class gangster thriller The Gentlemen, where it transports Esposito's billionaire character to give a drug-manufacturing aristocrat an offer he can't refuse.

Interestingly, the company that owns the actual aircraft is Bandersnatch Ltd Partnership Inc. 'Bandersnatch' is the title of a well-known episode of Netflix-produced Black Mirror.

Two of the helicopters were equipped with ball cameras, filming the other two, indicating they may be part of a television or film production, the Mirror reports.

In response to queries about the helicopters, one social media user offered an explanation, saying: "There is film work at Greenwich pier today so probably that."