Cycling on the footpath?

[Danfour20]

while in hull i received a fine for cycling on the footpath, 30 pounds which i paid, however when i moved to birmingham i noticed many of the police on bicycles ride on the footpaths (not specific bike paths just a normal footpath) i asked the police if it was illegal to ride on the footpaths in birmingham and he said no, i recently moved back to hull and received a 30pound fine yesterday for cycling on the footpath. why is it ok to do it in birmingham but not in hull?? im really pissed of about this as it is extremely dangerous on the roads. and when i ride on the footpath i go at walking pace when near pedestrians or get off depending on the situation. at the end of the day even if i was to run someone over going full pace on my bike (which i wouldn't) i aint gona do no wear near as much damage to a pedestrian as what a car could do to me while on the road. where can i complain?