Tens of thousands of people lined the streets of London to watch the Mayor’s St Patrick’s Day parade. Dressed in green, and holding Irish flags, onlookers were treated to pageantry, floats and marching bands. The crowds also gathered in Trafalgar Square to see live Irish music and dancing.
Source: http://www.imlookingforanitjobinlondon.co.uk/london-st-patricks-day-news/