What exactly does "first floor" flat mean in adverts?

I've been searching a lot lately on different lettings websites and rightmove trying to find a place to live prior to our move. We're looking for a ground floor flat. Thing is, the pictures accompanying the ads seem to show the flats being on the second floor, instead of the "first floor". I know this is true for France but I thought the UK followed the US way of thinking. Can someone clear this up for me? Should we be looking for "ground floor" or "first floor"?

Thanks!

If you want to be on the ground floor, then look for ground floor flats.
First floor is the floor above the ground floor.

http://en.wikipedia.org/wiki/Storey#British.2FEuropean_scheme

I thought the UK followed the US way of thinking.

In many things, maybe, but not in the matter of naming floors. The first floor is the first floor above the ground. In lifts ("elevators") the buttons sometimes go G-1-2-3-4 etc and sometimes 0-1-2-3-4.

Tremula - I've seen it like that in France but never noticed it in London. Huh. Alright then I will begin looking for ground floor flats! Thanks everyone for your responses

Ground floor versus the first floor nomenclature is probably the one thing that gets me into a tizzy