If anything, the law is now clearer on this matter due to a successful prosecution in 2011. You cannot legally use a Segway PT on the sidewalk/pavement in the UK (unless it is private land and you have the land owner's permission)
Although things have moved on and I think another similar case might result in a different outcome.
Here is the lowdown on the prosecution:
http://www.legalisesegways.co.uk/cms...aspx?PageId=21
And here is our hope for the future:
http://www.legalisesegways.co.uk/cms...aspx?PageId=25