The flag is on top of a building called the FACT building in Liverpool, England. People have been taking pictures from nearby rooftops, but nobody has managed to get close enough to take it yet.
This picture was posted about 20 mins or so ago. The issue is he can't get over to the flag because there is a gap where the roof drops down.
Here is a simple schematic. Our hero seems to be on top of the apartment building but cannot get across.
Here are the blueprints for the entire FACT building.
I will keep this post updated.
Edit: Motivational material
Edit 2: It appears the guy who was taking pics on the roof was on the other side of the rooftop, meaning he could have captured the flag, but did not. I suspect this is due to there being a door that opens out of the roof. If someone runs for the flag and that door opens, they may not be able to climb back over to the other rooftop before they are caught.
The building opened an hour ago so hopefully someone will scout it out soon, so the flag can be taken tonight.
He's from Liverpool, what do you expect?