Police officers in Belfast were pelted with fireworks and bricks in the Carlisle Circus area in the north of the city tonight.
Terry Spence, chairman of the Northern Ireland Police Federation, which represents rank and file officers, said: "Their bravery and courage is in stark contrast to that of the cowardly thugs responsible for trying to murder them."
More top news
The Office for National Statistics said gross domestic product grew by 0.1%.
William's comments came during a surprise appearance at an event scheduled for just his brother.
Matt Campbell, who collapsed just a few miles from the finish line, had hoped to raise £2,500.