How often have you seen a military helicopter land on Hampstead Heath?

Most likely, you've seen it happen remarkably frequently.

Often, they land moments from Parliament Hill Lido - quite the surprise if you're there for a swim.

Mysteriously, the helicopters seem to rest for a short period of time before lifting off again minutes later and disappearing over the cityscape.

The choppers have even been heard during the middle of the night between 11pm and 4am.

The RAF has now explained the helicopters are permitted to land on the heath.

The Ministry of Defence (MoD) said the helicopters have recently been carrying out exercises across London to help train crews for ongoing missions in the UK and abroad.

The pilots are being trained to cover a range of RAF operations, including assisting with the pandemic efforts in the UK and hurricane relief work in the Caribbean.

The RAF are currently helping out in Operation Rescript, a nickname given to the armed forces response to the pandemic.

The operation is the UK’s biggest ever military operation in peacetime according to the MoD.

The RAF are also training helicopter pilots to support Operation Ruman which helps with the relief efforts taking place in the Caribbean following devastating hurricanes in 2017.

The pilots train in a variety of locations to best train for different scenarios they could encounter across the world.

As well as training on Hampstead Heath the RAF’s teams have been training in Bristol, South Wales, Birmingham, Manchester and the Wirral.

The MoD also explained they try to notify local communities of any training activities, particularly in areas that may not be used to seeing helicopters, but they are not able to explain the full details for security purposes.

The MoD added that it is likely to continue to use Hampstead Heath for training exercises but they were unable to say how often they will do so - because there are so many factors that impact decisions.