Jarvis joined the Liberal Democrats in 2018, having been a "lifelong
Labour voter". She stood in
Southampton Itchen in the
2019 general election, coming third with 5.3% of the vote when the seat was won by
Conservative Royston Smith with a narrow majority over
Labour. In
2022 she was elected as an
Eastleigh Borough Councillor for the Hamble and Netley ward, with a majority of over 1000. In the
2024 general election she was elected as the Liberal Democrat MP for
Eastleigh, winning the seat back from the Conservatives for the first time since 2015 and overturning a
notional majority of 8,641 (calculated as the likely outcome of the 2019 election on the 2024 boundaries). She had a majority of 1,546 (3.3%) over the Conservative candidate; there were six candidates and a
turnout of 66%. She chose not to stand down as a Borough Councillor and told journalists she would donate her councillor allowance to charities. In September 2024, she made her maiden speech in the House of Commons during a debate on Great British Energy. On 21 October 2024 she was appointed to the House of Commons
Culture, Media and Sport Select Committee. In November 2024, Jarvis voted for the
Terminally Ill Adults (End of Life) Bill. She stood down as a councillor in January 2025. == Personal life ==