The Battle of Flers–Courcelette commences.

The Battle of Flers–Courcelette, which ran through September 22, commenced.  The battle is notable for the commitment of Canadian and New Zealand troops to the Battle of the Somme, of which this is part, and for the first British use of tanks in World War One, and hence, the first use of tanks.

Four Mark I tanks filling with petrol, Chimpanzee Valley, 15 September (Q5576).  Note the mounted soldiers.

This image was created and released by the Imperial War Museum on the IWM Non Commercial Licence. Photographs taken, or artworks created, by a member of the forces during their active service duties are covered by Crown Copyright provisions. Faithful reproductions may be reused under that license, which is considered expired 50 years after their creation.

The Commonwealth forces did advance, but there was less achieved than had been hoped for.  Critics have focused somewhat on the ineffective use of tanks, both then and now, but then they were a new weapon.  Some, such as Winston Churchill, who was significant in the development of the tank, felt that had tanks been used en mass, a breakthrough might have occured.