Stanton Williams' solution is a sequence of three big moves. There is a new pedestrian approach ramp up the northern side of the Tower's moat. There is a sequence of three rather elegant rectangular steel-and-glass pavilions containing everything from ticketing to coffee kiosks and souvenir sales - all set well back on the western side of the hill. And there is the big square, 656 feet long by 165 feet wide, sloping downhill at an exact gradient of 1 in 20. Making it meant closing a road. Paved in York stone at the top of the hill, it gives way to granite setts and broader granite slabs lower down. But it is not just a sloping square. It is also a look-out point. By clearing away all the clutter on the eastern side and making a flight of broad steps down into the top of the moat, Stanton and Williams have revived the 18th century idea of the ha-ha. From the west, the square seems to flow straight to the Tower, with no barrier at its edge. Move closer to the edge, and you realize that it's a visual framing device. There is a barrier: it's just down the slope, out of sight.

There were some raised eyebrows as the work progressed, with some Victorian railings being removed and worries raised about the stability of the moat walls as sections crumbled. Archaeological finds were made - you can't stick a spade in the ground round here without unearthing something or other - and some would have liked longer to study them. The square had to be made in small sections so as to maintain public access to the Tower. So it was a complicated, lengthy business, but now it is done.