She was born Nelia Muspratt, a daughter of Clifford Muspratt and Bertha Noble. in Hampstead, London. She was part of an established Liverpool Liberal family; she was the niece of the MP Max Muspratt and the suffragistNessie Stewart-Brown and granddaughter of the Industrialist Edmund Knowles Muspratt. She was educated privately. On 29 May 1947 she married Derek Penman. They had three daughters, Fiona, Alison and Wendy. The marriage was dissolved in 1974.
While in her early twenties her activity in the Liberal party took the form of membership of the 8.30 Club, a young Liberal group that monthly debated international issues from its founding in 1936 to 1939. In 1936 she advocated the creation of an International Police Force under the control of the League of Nations. In 1937 she advocated the suppression of Fascist and Communist propaganda. In 1938 she was selected as Liberal prospective parliamentary candidate for Liverpool Wavertree for a general election expected to take place in 1939/40. It was not a promising seat, although the Liberals had won the seat in 1923, they had come fourth at a by-election in 1935. During the war, she continued as PPC for Wavertree and spoke at the 1941 Liberal Assembly in favour of the creation of a Ministry of Civil Defence. She did not contest Wavertree and instead was Liberal candidate for the Sevenoaks Division of Kent at the 1945 general election. Sevenoaks was a safe Conservative seat that the Liberals had not won since 1923. They were second in 1935 when no Labour candidate stood. Labour had no candidate in place in 1939/40. A two-party contest between Conservative and Liberal would have been an attractive prospect for any Liberal in 1945. However Labour intervened and pushed the Liberals into third place; Four general elections later she stood again at Sevenoaks, but did no better; She stood again at the following election and slightly increased her vote share; She was Chairman of the Liberal Party's Social Security Panel, before resigning in 1977 to become President of the Women's Liberal Federation. Penman died in August 2017 at the age of 101.