7th - Harriet Harman
As the longest-serving female MP in the House of Commons, this Labour giant is the unofficial Mother of the House. First elected at the 1982 Camberwell and Peckham by-election, Harman won the seat with 50% of the vote.
During her 35 years in parliament, Harman has served in a range of roles including numerous positions in the shadow cabinet before New Labour came to power in 1997. During Labour’s time in government, she served as Minister for Women and Equality, as well as Leader of the House of Commons. She has served as acting Labour leader on two occasions.
Harman recently claimed that she would have defeated Ed Miliband in the 2010 leadership election had she stood in the contest, as reported by the Guardian.
6th - Frank Field
First elected at the 1979 general election when Thatcher came to power, this Labour MP has been in parliament for almost forty years. He currently chairs the Work and Pensions Select Comiittee.
5th - Barry Sheerman
Like Field, Sheerman was also elected at the 1979 election. The Labour MP for Huddersfield previously taught at the University of Wales, and was the Education Select Committee Chair during most of New Labour’s time in power.
4th - Geoffrey Robinson
This Labour MP was first elected at the Coventry North West by-election in 1976 caused by the death of Labour MP Maurice Edelman, who had first been elected in 1945 when Labour formed its first ever majority government under Clement Attlee. Robinson held the seat with 54% of the vote in June’s election, and between 1996 and 2008 he owned the New Statesman.
3rd- Peter Bottomley
Bottomley is the first Conservative MP included in the top seven, but there is one more further down the list. Bottomley was first elected at a by-election in 1975 following the death of the Labour MP. It, and its successor constituency, has voted Tory ever since.
2nd - Dennis Skinner
This Labour giant was first elected for Bolsover way back in 1970, when Edward Heath won a slim majority for the Conservatives, in the second of four great electoral battles with Harold Wilson. Skinner is a left-wing firebrand, who is approaching the start of his sixth decade in the chamber.
1st - Kenneth Clarke
The former Tory chancellor, two-time leadership contender and committed Europhile is the longest-serving MP in the House of Commons. First elected in 1970, Clarke earnt the title of Father of the House earlier this year. Although Skinner and Clarke started at the same time, Clarke holds the title as the longest-serving MP as he was sworn in first way back in 1970.
A full list of MPs by seniority from the 2015-2017 parliament can be accessed here. Seniority for the 2017-present parliament is based of this list.