Residents flocked to social media trying to work out what type of aircraft was flying over on Sunday afternoon.

On September 17, at around 1.20pm, some people in Kings Langley said they saw what looked like a military aircraft.

One person suggested it could have been a Douglas C 47, while others thought it was a Lancaster bomber.

The Ministry of Defence has confirmed to the Watford Observer that it was a Lancaster Bomber, PA474, that was built as a B Mk 1 (B1).

Watch the video, filmed by Emma Matthews, of the Lancaster Bomber flying over the Rudolf Steiner School in Kings Langley.

The MoD spokesperson said there is only one flying Lancaster in the UK, which is part of the Royal Air Force Battle of Britain Memorial Flight.

There are only two airworthy Lancasters in the world – 7,377 were built.

On Sunday, the Lancaster started at Stamford in Lincolnshire at 11.24am, headed to Flixton in Suffolk at 12.11pm, then to High Wycombe and Princess Risborough in Buckinghamshire at 1.23pm and 1.29pm.

Its last stop was in Wickenby in Lincolnshire at 2.25pm.

Between May and September, Spitfires, Hurricanes, a Lancaster, a C47 Dakota, and two Chipmunk aircraft are seen in UK skies.

They are used to celebrate and commemorate public and military events such as Trooping the Colour, major airshows, and flypasts for public events.