MADRS22 making circles above North Sea

Hello people,

I am very new to this forum and started a new hobby 'watching Flightradar24' last week :-)

Because I am very new I need to find out all things (on my own).

Can somebody explain me why this plane MADRS22 is making circles above the North Sea?

It's a plane of The Royal Airforce (UK) with registration ZZ331 and it doesn't have a destination.

Thanks for the answer,

Greets,
Martijn, Breda, The Netherlands