The British had substantially increased the amount of artillery on the Western Front after the Battle of Loos in late 1915 but the length of front to be bombarded on the Somme led to the preparatory bombardment being planned to last for five days. There had been a debate about the merits of a short hurricane bombardment but there were insufficient guns quickly to destroy German field defences and be certain that barbed wire was cut, given the dependence of the artillery on air observation and the uncertain weather. The artillery had to cut barbed wire and neutralise German artillery with counter-battery fire. The British artillery fired more than shells during the preliminary bombardment, more than in the first year of the war. On 1 July, another were fired; the guns could be heard on Hampstead Heath, away. While this weight of bombardment was new for the British, it was common on the Western Front; at the Second Battle of Artois in May 1915, there had been a six-day preparatory bombardment with over shells. British shell production had increased since the shell scandal of 1915 but quality had been sacrificed for quantity and many shells failed to explode. Shrapnel shells were virtually useless against entrenched positions and required accurate fuze settings to cut wire; very little high explosive ammunition had been manufactured for field artillery. The French Sixth Army had guns and howitzers, with a much larger supply of high explosive ammunition for field artillery and far more experienced personnel.