By February 1915 the submarine blockade of the British Isles has begun, and in that month also the BEF is engaged in the Battle of Neuve Chapelle. The Western Front is relatively stabilised, with limited attacks by both sides, but in April the Germans begin to use poison gas. On the Eastern Front, the winter battle of Masuria is fought in February. Meanwhile hostilities are escalating in the Middle East, and, after failed naval attacks on the Dardanelles in February and March, the Gallipoli landings begin at the end of April. At sea, the Royal Navy has won the Battle of Dogger Bank in January. And in January a new gallantry award for officers has been instituted, the Military Cross – five Corsham men will earn this medal.