How many square miles inside m25?

Answer 1

250

Answer 2

This is technically impossible to answer as the M25 is not a complete circle - it is a C shape: the Dartford crossing is actually an A road (the A282).

However, ignoring this [obscure fact], a full lap of the M25 plus Dartford crossing is approx 118 miles in length, and assuming it to be a circle, its area would be approx 1100 sq miles - as the M25 wiggles quite a bit, the area is slightly less than this.