Munt initially joined the international division of Midland Bank, before leaving after a year to join a local firm of solicitors. After three years, she started working for a local hotel, and after two years moved to East Anglia working in the company's sales and marketing team, before moving to personnel and later customer care training. She then worked in administration for South Essex College at their Southend-on-Sea campus, before moving into teaching. She then worked for a period in social services, working with adults with learning difficulties. She also worked part-time as a volunteer for both Childline and the Environmental Investigation Agency. She married in 1992, and had two children. She spent time working as the personal assistant to former international cricketer Phil Edmonds. She then started working for a solicitors' firm, before being asked to move by a former company partner to join the team at Forsters solicitors. She also spent five years as a Regional Advisory Panel member for the National Lottery Charities Board.
Political career
Munt had joined the Labour Party in the early-1990s, but left after their election victory in 1997 due to the centralisation of party policy. She then campaigned in the late-1990s in Suffolk to preserve a Victorian school against a proposed development plan, where she met Andrew Phillips, Baron Phillips of Sudbury, and in 1999 after attending a party conference and meeting Norman Lamb, Munt joined the Liberal Democrats. Munt was the party's candidate for South Suffolk at the 2001 general election, when she finished in third place with a 24.9% share of the votes. She also contested Ipswich at the 2001 by-election following the death of Labour MP Jamie Cann, coming third with 22.4% of the vote. As her father lived in Wells, Somerset, a few weeks after her defeat, the local party committee offered her the option of standing at the Wells constituency. She stood at the 2005 general election, finishing in second place to sitting MP David Heathcoat-Amory with a 37.8% share of the vote.
Westminster: 2010–2020
Munt was elected as the Member of Parliament for Wells at the 2010 general election with a majority of 800 votes over David Heathcoat-Amory, who admitted that his involvement in the United Kingdom Parliamentary expenses scandal played a part in his defeat. Munt was a party whip in the House of Commons from 2010 until March 2012, although she threatened to resign from the post if the Trident nuclear missile system was renewed. She was later appointed as Parliamentary Private Secretary to Business Secretary Vince Cable. In July 2010, newspapers revealed details of an investigation by Sedgemoor District Council into her claims of single person council tax discount while having more than one other adult male registered to vote at her home, including a local GP, the broadcaster Andy Kershaw and the media advisorfor the family of Madeleine McCann. On 6 September 2010, Sedgemoor District Council said that there were now no criminal proceedings relating to the single person discount on Council Tax and Munt was cleared of any wrongdoing. On 27 January 2015, Munt resigned as PPS to Cable after she voted for a Commons amendment – not supported by the government – calling for a moratorium on fracking in the UK. On 7th of May 2015 Tessa lost the Wells parliamentary seat, in a shocking defeat, to the Conservative party candidate James Heappey by 7585 votes. Tessa continued as the Liberal Democrat candidate for Wells in the following two general elections of 2017 and 2019 failing to reclaim the seat on both attempts, seeing the conservative candidate increase his majority to 9991 in 2019.
County Hall: 2017–present
On 5 May 2017, at the 2017 UK local elections, she was elected as a councillor in Somerset, beating Somerset County Council leader, John Osman, by the slim majority of 95 votes. She is widely expected to contest the seat once more in the county elections in May 2021.