Chamberlain was born in Edgbaston in 1862. Her father was Joseph Chamberlain, who later became Mayor of Birmingham and a Cabinet minister. Her mother was Florence Kenrick, who was the cousin of William Kenrick MP. Beatrice was her parents' eldest child and the birth of her younger brotherAusten Chamberlain took the life of her mother. As a girl Beatrice dominated her more shy brother Austen. Beatrice was devoted to her aunt, Caroline Kenrick. Her early education was at Edgbaston High School for Girls. Her father married again and had four children, but the birth of the fifth child took the life of his second wife, Florence, in 1875. Beatrice took over as de facto mother and governess to her half siblings which included Neville Chamberlain who would be the Prime Minister who declared war on Germany. Beatrice continued her education in Fontainebleau at Les Ruches, a private school for girls. By 1888 she was back in Edgbaston where she was able to release herself from the role of châtelaine to her father when he married for the third time. Beatrice was free to gather funds for the Children's Country Holidays Fund whilst she helped manage primary schools in Hammersmith and Fulham. Her new stepmother, Mary, introduced her to leading American politicians including Theodore Roosevelt and William Howard Taft. Her sister Ethel died in 1905. Her brother Austen turned to Beatrice when he was the Chancellor of the Exchequer. She able to serve as an advocate for Austen with the wives of those who were opposing him. Being fluent in French, she helped organise the French Wounded Emergency Fund at the start of World War I after her father died. Her fund raising for hospitals in France was so successful that she was asked to extend her money gathering across the country. She was involved with preparations for peace acting as an advisor to the Ministry for Reconstruction. Change she could see would include giving the vote to some women. All of the Chamberlain family had opposed this change and although Beatrice was involved in creating women's groups within the Unionist Party, she now accepted it as inevitable. Chamberlain died in Kensington in 1918 in the flu pandemic. Her obituary noted that she had the "mind of a Great Man". Her siblings had all admired her. Her brother, Austen, went on to win a Nobel Peace Prize and her half siblings all had notable lives.
