On 4 August 1914 Britain was reluctantly dragged into the first general European war for a century, in order to honour its treaty obligations and meet the perceived threat to British interests from German military expansionism. The following four years proved to be one of the bloodiest episodes in world history. While Britain suffered fewer casualties than some of the other belligerents, the British army and navy nevertheless lost at least 616,382 men, while 1,656,735 were wounded– many facing a lifetime of disability or disfigurement. The onset of War created immediate problems for munitions production, by cutting off supplies of many items for which Britain relied on continental producers, such as magnetos, synthetic dyestuffs, and optical glass. The First World War had a major long-term impact on regional disparities. Defence production concentrated light munitions work in the south and West Midlands, while increasing the relative specialisation of 'outer-Britain' in its narrow range of dominant staple export industries.