Just reported this guy whilst on expert as i was flying. He took off from EGLC and followed me on the whole approach into EGLL not using the UNICOM or having any reaction to me being in front of him. It was very frustrating and you expect more from people on the Expert server. Even with the stricter rules on the Expert server i think they could be a bit stiffer to avoid this happening. Baring in mind its not the first time.