Calum Miller is the Liberal Democrat MP for Bicester and Woodstock, having first been elected to parliament at the 2024 general election.

In that election, Miller won 19,419 votes, representing 38.7% of the vote. The Conservative candidate, Rupert Harrison, received 14,461 votes (28.8%), while the Labour candidate, Veronica Oakeshott, secured 8,236 votes (16.4%). Miller was duly elected with a majority of 4,958.

The Bicester and Woodstock constituency, newly created for the 2024 election, is located in Oxfordshire, in the South East of England. It was formed from parts of the former Banbury, Henley, Oxford West and Abingdon, and Witney constituencies.

Political Career

Miller currently serves on the Liberal Democrat frontbench as foreign affairs spokesperson. He was appointed to this role in September 2024.

Miller delivered his maiden speech on 3 September 2024 during a debate on the Passenger Railway Services (Public Ownership) Bill.

In it, he said: “Each [river] has to carry its unfair share of pollutants from Thames Water’s sewage spills. Tackling the pollution of our rivers and waterways was a common concern among my constituents during the election campaign, and I welcome the prime minister’s undertaking to work across parties to address this scandal.”

He added: “My constituents understand the need for more homes for local residents, and especially for those who cannot access social housing, but they want to know that sufficient infrastructure will accompany new homes.

“We must make sure that these services are funded and delivered before new homes are released.”

Before entering parliament, Miller was elected as a Liberal Democrat councillor on Oxfordshire County Council in May 2021. He stood down from this post in May 2025.

Political Views

The Liberal Democrats (or Lib Dems) are a liberal political party, occupying the centre to centre-left ground in British politics.

The preamble to the Lib Dem constitution begins: “The Liberal Democrats exist to build and safeguard a fair, free and open society, in which we seek to balance the fundamental values of liberty, equality and community, and in which no-one shall be enslaved by poverty, ignorance or conformity.”

The Liberal Democrat autumn conference in 2021 ratified a policy paper entitled What Liberal Democrats Believe. The paper, an attempt to expand on the constitution’s preamble, was framed around seven “principles and values”.

The party’s core values were described as “liberty, equality, democracy, community, internationalism and environmentalism.”

Miller is a member of the Green Liberal Democrats, an official environmental group within the Liberal Democrats. It aims to “promote a green approach to policy formation within the Liberal Democrats” and “develop links with the wider green movement.” The grouping, formed in 1977 as a faction within the Liberal Party, is “committed to a net-zero and nature positive future and driving ambition across the national party and in local governance.”

Miller was endorsed by local groups of the cross-party organisation Compass during the 2024 general election. Compass is a thinktank and campaign group. As part of its “Win as One” campaign in the 2024 election, local Compass groups backed a slate of progressive candidates who had pledged their support for electoral reform. The central aim of the initiative was to elect a “caucus” of MPs who would champion the cause of replacing the first past the post electoral system.

Miller is listed as a supporter of the all-party parliamentary group (APPG) for fair elections – a cross-party group of MPs and peers that campaigns for electoral reform. The group’s stated aims include replacing the first past the post (FPTP) voting system with a form of proportional representation, eliminating “dark money” and “undemocratic influence” from politics, and countering disinformation.

In December 2024, Miller voted in favour of the Elections (Proportional Representation) Bill – introduced by Liberal Democrat frontbencher Sarah Olney under the 10-minute rule procedure. The bill sought to “introduce a system of proportional representation for parliamentary elections and for local government elections in England”.

A total of 138 MPs supported the bill – with 136 opposed. Notably, 59 Labour MPs backed Olney’s bill.

Introducing the bill, Olney told the House: “First past the post is a broken and unfair system. This summer, the Labour party won a landslide election victory, securing 63% of seats in the House of Commons in return for just 34% of the vote.

“The system leaves millions of voices unheard and creates a divisive, adversarial political climate where collaboration is discouraged and accountability is often sidestepped.”

Brexit and Europe

Customs union vote (2025): In December 2025, Miller voted in favour of the UK-EU Customs Union (Duty to Negotiate) Bill. The bill, introduced under the 10-minute rule procedure by Liberal Democrat Europe spokesperson Al Pinkerton, sought to mandate the government to enter into negotiations with the European Union to establish a bespoke customs union. In total, 13 Labour MPs joined the Liberal Democrats in supporting the motion, while the majority of the party abstained.

Assisted dying

Miller voted against the Terminally Ill Adults (End of Life) Bill, better known as the assisted dying bill, at both second reading (November 2024) and third reading (June 2025).

In a statement setting out his position, Miller said: “As legislators, we have the job of trying to work out what is best for society as a whole. Even if we are convinced a piece of legislation will benefit one individual, we have to be sure that its full effect will benefit more people than it might harm.”

Miller was one of 15 Liberal Democrats to vote against the assisted dying bill at third reading.

Social values and conscience issues

Miller was one of the 38 Liberal Democrat MPs who voted for the Tobacco and Vapes Act 2026 at its House of Commons third reading.

Abortion decriminalisation (2025): Miller voted in favour of a backbench amendment to the Crime and Policing Bill that sought to decriminalise abortion in England and Wales in June 2025. The amendment, which was passed by a majority of 242 votes, removed women from the threat of prosecution for ending a pregnancy at any stage. As an issue of conscience, MPs were allowed to vote according to their personal beliefs.

Palestine

Palestinian recognition letter (July 2025): In July 2025, Miller was among the over 254 MPs to sign a cross-party letter calling for the government to immediately recognise the state of Palestine. The letter called on the prime minister and foreign secretary to recognise Palestine at the UN Conference then taking place in New York.

Before Politics

Calum Alexander Miller spent most of his adult life in Oxfordshire before becoming an MP.

Miller studied philosophy, politics and economics (PPE) at the University of Oxford, graduating in 1999. He obtained a master’s degree in international relations in 2005.

Miller spent nearly a decade in the civil service across several departments before entering frontline politics, including at the Treasury, Foreign and Commonwealth Office, Department for International Development (DFID) and the Cabinet Office.

He served successively as principal private secretary to the cabinet secretary and head of the UK civil service, Sir Gus O’Donnell, (2009-2010) and to the deputy prime minister, Nick Clegg, (2010-2012).

Miller left the civil service to serve as chief operating officer at the Blavatnik School of Government, University of Oxford.

Personal Life

Miller is married and has four children.

His mother was a social work manager and his father was general secretary of the Scottish Liberal Democrats before training as a Church of Scotland minister.

He is a member of both the Church of England and the Church of Scotland.

Trivia

Miller reportedly received a “well done” text from Sue Gray, the serving chief of staff to Keir Starmer, upon his election as an MP. Gray was once Miller’s line manager in the Cabinet Office.