At the turn of the century, Herbert H. Asquith was considered one of the rising young stars of the Liberal party. An accomplished barrister, he was along with Sir Edward Grey and Richard Burdon Haldane, a member of the so-called "Liberal Imperialist" section of the party and as such supported British involvement in the Boer War of 1899-1901. He was an MP for 20 years, Home Secretary under William Gladstone, and Chancellor of the Exchequer under Henry Campbell-Bannerman before becoming Prime Minister on the latter's retirement in 1908.
His performance as Prime Minister is the subject of much dispute. He was undoubtedly a man of high intelligence and personal integrity. Asquith lacked the charisma of David Lloyd George and Winston Churchill, however, and as an administrator he was lackadaisical. As his management of the Home Rule crisis of 1912-14 demonstrated, he postponed difficult decisions rather than confronting them head-on, and had little skill in coordinating the activities of the members of his cabinet. A social conservative, he opposed women's suffrage.
At the onset of the First World War, Asquith took an uncharacteristically firm stance, and did not hesitate to back British entry into the war on the side of France. In directing the British war effort, he did not fully appreciate the need to abandon peacetime methods of governance. He streamlined the political administration of the war only slowly and with great reluctance. The so-called "shell crisis" of 1915 forced him to appoint Lloyd George as Minister of Munitions and form a coalition government that remained dominated by Liberals, but Asquith continued to run the economy and the cabinet on much the same principles that had been current before the war. The institution of conscription in the spring of 1916 came only after Asquith felt it was impossible to resist any longer, and did much to disillusion a man who had staked his reputation on Liberal principles, among which was that of "volunteerism."
Keeping in mind his many faults, Asquith's downfall in December 1916 was nonetheless a sordid affair that reflects little credit on Lloyd George and his allies in the Conservative party. In some respects this political crisis was a direct result of the Battle of the Somme in the summer and fall of that year. The carnage of this terrible battle convinced many politicians in both parties that drastic measures, far beyond anything Asquith was willing to countenance, would be necessary to win the war. More ominously, some politicians and generals were convinced that Asquith was allowing, if not encouraging, defeatism to engulf the government. There is no evidence whatsoever to support this contention, which Lloyd George and Lord Northcliffe nevertheless did their best to foment during and after the war. Asquith was personally devastated by the death of his son Raymond during the Somme battles, but remained steadfast in his desire to see the war through.
Lloyd George successfully engineered his replacement of Asquith as Prime Minister in the new coalition formed in December 1916. Asquith remained active in politics, even regaining his place as leader of the Liberal party in the 1920s, but his reputation never truly recovered from the war.
Sources: The source material on Asquith and the British politics of World War One is massive. The works listed below are only a starting point for more serious research.
Cassar, George H. Asquith as War Leader. London: Hambledon Press, 1994.
Hazelhurst, Cameron, "Asquith as Prime Minister, 1908-1916," English Historical Review 85 (July 1970): 502-531.
Jenkins, Roy. Asquith. London: Collins, 1978.
Koss, Stephen. Asquith. New York: St. Martin's Press, 1976.
Spender, J.A., and Cyril Asquith. Life of Henry Asquith, Lord Oxford and Asquith. London: Hutchinson, 1932.
Wilson, Trevor. The Downfall of the Liberal Party, 1914-1935.
Ithaca: Cornell University Press, 1966.