Chamberlain was elected with almost 70% of the vote and a majority of 6,833. He was 49 years old, which remains to date the greatest age at which any future Prime Minister has first been elected to the Commons. Chamberlain threw himself into parliamentary work, begrudging the times when he was unable to attend debates and spending much time on committee work. He was chairman of the national Unhealthy Areas Committee (1919–21) and in that role, had visited the slums of London, Birmingham, Leeds, Liverpool and Cardiff. Consequently, in March 1920, Bonar Law offered him a junior post at the Ministry of Health on behalf of the Prime Minister, but Chamberlain was unwilling to serve under Lloyd George and was offered no further posts during Lloyd George's premiership. When Law resigned as party leader, Austen Chamberlain took his place as head of the Unionists in Parliament. Unionist leaders were willing to fight the 1922 election in coalition with the Lloyd George Liberals, but on 19 October, Unionist MPs held a meeting at which they voted to fight the election as a single party. Lloyd George resigned, as did Austen Chamberlain, and Law was recalled from retirement to lead the Unionists as Prime Minister. Many high-ranking Unionists refused to serve under Law to the benefit of Chamberlain, who rose over the course of ten months from backbencher to Chancellor of the Exchequer. Law initially appointed Chamberlain Postmaster General and Chamberlain was sworn of the Privy Council. When Sir Arthur Griffith-Boscawen, the Minister of Health, lost his seat in the 1922 election and was defeated in a by-election in March 1923 by future Home Secretary James Chuter Ede, Law offered the position to Chamberlain. Two months later, Law was diagnosed with advanced, terminal throat cancer. He immediately resigned and was replaced by Chancellor of the Exchequer Stanley Baldwin. In August 1923, Baldwin promoted Chamberlain to the position of Chancellor of the Exchequer. Chamberlain served only five months in the office before the Conservatives were defeated in the 1923 general election. Ramsay MacDonald became the first Labour Prime Minister, but his government fell within months, necessitating another general election. By a margin of only 77 votes, Chamberlain narrowly defeated the Labour candidate, Oswald Mosley, who later led the British Union of Fascists. Believing he would lose if he stood again in Birmingham Ladywood, Chamberlain arranged to be adopted for Birmingham Edgbaston, the district of the city where he was born and which was a much safer seat, which he would hold for the rest of his life.