This was the biggest nationalist rally in recent memory - perhaps ever. Well before the march started, thousands of people flowed over Blackfriars bridge, or came up from Waterloo station, flags everywhere, hailing from everywhere - from Yorkshire roses to the diamond of the Isle of Wight.
What exactly it was that "United the Kingdom" was left vague, for people to cheer their own particular cause. Sky's Tom Cheshire reports.
The Wall