I'd like to see you fly your state aircraft through UK airspace without following the rules of the air. Can you imagine the consequences.
Dear god, are you incapable of following a link, or deliberately ignorant....
Come back when you read and understand the agreed regulations......
Article 3
Civil and state aircraft...........
c) No state aircraft of a contracting State shall fly over the territory of another State or land thereon without authorization by special agreement or otherwise, and in accordance with the terms thereof.