[1][2] In May 2024, Mathias was selected as the Conservative candidate for Maidenhead for the 2024 general election, following the retirement of the incumbent MP and former Prime Minister Theresa May.

[7] Her grandfather, Fred Mathias, played rugby and cricket for Glamorgan and in 1918 was awarded the Military Cross after his exploits flying over enemy lines in Belgium and France.

[6] Soon after graduating in medicine, Mathias was a refugee worker for the United Nations Relief and Works Agency (UNRWA) in the Gaza Strip and treated HIV, AIDS and tuberculosis patients in Africa.

[15][16] However, she voted differently from her colleagues on occasion, most consistently for: allowing terminally ill people to be given assistance to end their life, requiring pub companies to offer pub landlords rent-only leases and for unilaterally guaranteeing the rights of EU citizens living in the UK;[15] (she was one of only two Conservative MPs to vote against the government on this).

[20] She reacted negatively to the UK government's decision to begin consultation for the construction of a third runway, declaring expansion "misguided and not in the nation's interest".