Today marks the 100th anniversary of the beginning of the Battle of Passchendaele (aka the Third Battle of Ypres), one of the most controversial and bloody moments of the Great War. The battle lasted three months, at an estimated cost of 250,000 causalities on the Allied Forces lead by Field Marshal Haig, and a similar number of German deaths as well. Debate remains to this day about how effect the battle was, with many of the view that the battle achieved nothing constructive overall. The BBC presents live coverage of the remembrance hosted by Kirsty Young and Dan Snow. Attending the event among others will be the King and Queen of the Belgians, and the Duke and Duchess of Cambridge. World War One Remembered: Passchendaele is on BBC Two at 19.00.