wet weather turned battle into mudbath

Prime Minister Theresa May, the Prince of Wales and the Duke of Duchess of Cornwall will join descendants of soldiers who fought at Passchendaele at events in Belgium tomorrow and Monday.

They will help mark the start of one of the bloodiest campaigns of the First World War.

The Battle of Passchendaele left hundreds of thousands of men dead and wounded but was not the decisive breakthrough the British had hoped for, as soldiers were hampered by unseasonal wet weather and stiff German resistance.

The battlefield in Belgium was turned into a hellish quagmire of mud and shell craters as the fighting went on during the summer and autumn of 1917.

Here are some of the numbers associated with the battle:

325,000: Estimated Allied casualties, including many Australian, New Zealand and Canadian soldiers. The Germans lost between 260,000 and 400,000.

4.25 million: Shells fired at the German lines from 3,000 big guns in the two weeks before the battle started - alerting them to an imminent attack.

103: Days that the battle lasted, between July 31 and November 10, 1917. 127mm: amount of rain (five inches) that fell on Passchendaele in August 1917. The average for the UK in August 2016, by comparison, was 85.5mm (3.4 inches).

32,000: Casualties they suffered during that period.

1,200: British casualties per 100 metres gained in those first opening three-day campaign of fighting.

Picture: PA. Ruined buildings in Ypres, Belgium.