100 years ago today, on 8 August 1918, the final decisive battle of the First World War began, Amiens. It was a offensive by the allies against he exhausted Germans and, unlike all previous offensives, it was an immediate unqualified success.

The startling advances after four years of piecemeal, limited gains were due to a number of factors. The arrival of the Americans and the possibilities of their almost unlimited industrial might; the deployment of hundreds of tanks; air superiority; the collapse of German morale, industry and even society plus the fact that the spread of Spanish flu in the German Army was more widespread than in Allied ranks.

On day one advances of up to eight miles were made with relatively little opposition and over 15,000 prisoners taken. A 15 mile gap had opened up in the German lines by the end of the first day.

Ludendorf was later to describe it as "the black day of the German Army".