Dhesi MP was elected as Member of Parliament for Slough (UK) in 2017, becoming the first ever turbaned Sikh MP in any European Parliament. He was re- elected in 2019.

In Parliament, he has served as a member of the Defence Committee, HCLG (Housing, Communities & Local Government) Committee, Parliamentary Private Secretary to the Leader of the Opposition, and was elected to serve as UK delegate to the NATO Parliamentary Assembly. He is Chairman of the All Party Parliamentary Group for Western Rail Link to Heathrow and spearheaded the campaign for National Sikh War Memorial. He is also currently the Shadow Minister for Railways.

Prior to Parliament, Tan studied Mathematics with Management BSc at University College London, MSc Applied Statistics at Oxford University, before an MPhil at Cambridge in South Asian history. After his studies, Tan ran his own construction company in Scotland. He also served for a decade as an elected councillor in Gravesham, where he subsequently became Mayor in 2011. During this time he became a Cabinet Member, Constituency Party Chairman and had many voluntary roles (School Governor; Alzheimer’s & Dementia charity Trustee; Mencap Society advisor and Independent Police Advisory Group member).