The plane bringing home Corporal William Savage, Fusilier Samuel Flint and Private Robert Hetherington has just landed at RAF Brize Norton.
Close family will spend time with the coffins before the cortege passes through the village of Carterton where friends and family will pay their respects as a memorial bell tolls.
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Two knives were found at the scene in Islington, North London, and the suspects fled on foot before being arrested.
The violence began after a counter-protester allegedly doused a female rally organiser with pepper spray.
As temperatures climb through the day, the warmest spots are likely to be across western parts of Northern Ireland and western Scotland.