noob question- when to use the sidewalk?



I'm in the UK and have to use the pavement in my area sometimes. I live near Birmingham and some of the roads are narrow but used heavily.

The pavements on these roads are hardly used by pedestrians. Most of them end up being turned into cycle lanes whenever the council feels like buying some paint...but odd cycle lanes that stop and start for no real reason.
 
When I commute, the world belongs to me, within reason. I try to obey the laws of the road ;>! and ride relatively politely. I use the road, the sidewalk, empty lots, alleys, you name it! As long as I am not endangering someone else or being rude, I try to be as creative as possible. Also, if I see a police officer I try to get legal out of respect, because they have their job to do.