On the backbenches

Bottomley contested the Vauxhall constituency in the 1973 GLC election and Woolwich West parliamentary seat in the February and October general elections of 1974,^[4] failing to defeat the sitting Labour MP William Hamling. Hamling died on 20 March 1975, and in the space of 18 months, Bottomley faced the electors of Woolwich West for a third time at the by-election on 26 June 1975.^[5] At this by-election he was elected as MP for Woolwich West with 48.8% of the vote and a majority of 2,382.^[5]

In 1978 he became the President of the Conservative Trade Unionists for two years.^[4] Bottomley became a trustee with Christian Aid in 1978 until 1984. In 1978, as a member of the Parliamentary Human Rights Group,^[6] he campaigned to prevent the anticipated assassination of Archbishop Óscar Romero^[7] and represented the British Council of Churches at the Saint’s funeral in El Salvador in 1980 when 14 people died around him.^[8] In 1979, days before the fall of the Labour Government, he made a visit to Washington, D.C., to indicate that Margaret Thatcher, if she became Prime Minister, would not lift sanctions on Southern Rhodesia nor recognise the government of Bishop Abel Muzorewa. He was for some years a member of the Conservative Monday Club as well as a member of the Bow Group and Tory Reform Group.^[4]

At the 1979 general election, Bottomley was re-elected as MP for Woolwich West with a decreased vote share of 47.3% and an increased majority of 2,609.^[9]

He has been chairman of the Church of England's Children's Society, a trustee of Mind and of Nacro and on the policy committee of One Parent Families. He served with John Sentamu on the successor committee to the Archbishop of Canterbury's commission that produced the report Faith in the City, and chaired the churches' review group on the Churches Main Committee. He is a member of the Ecclesiastical Committee and has been appointed the Parliamentary Warden at St Margaret's Church, Westminster. He has led the United Kingdom delegation to the Parliamentary Assembly of the Organization for Security and Co-operation in Europe (OSCE). He is an Hon. Vice President of WATCH, Women and the Church, supporting full equal acceptance of females.^[10]

In 1982, he became the Parliamentary Private Secretary (PPS) to the Minister of State at the Foreign and Commonwealth Office, Cranley Onslow. At the 1983 general election, Bottomley's constituency of Woolwich West was subject to boundary changes and was renamed Eltham; he won the new seat with 47.9% of the vote and a majority of 7,592.^[11] Following the election, Peter Bottomley became the PPS to the Secretary of State at the Department of Health and Social Security, Norman Fowler.

Member of the Thatcher Government

Bottomley became a member of Margaret Thatcher's government when he was appointed as the Parliamentary Under Secretary of State at the Department for Employment in 1984, moving sideways to the Department of Transport in 1986 to become the Minister of Roads and Traffic. He opened many news roads as Minister, including the Bulwick A43 Bypass in April 1986. In 1989 he moved sideways again to the Northern Ireland Office. He was dropped by Thatcher in 1990, when he briefly became PPS to the Secretary of State for Northern Ireland, Peter Brooke.

At the 1987 general election, Bottomley was re-elected as MP for Eltham with a decreased vote share of 47.5% and a decreased majority of 6,460.^[12]

Return to the backbenches

Since 1990, Bottomley has been a backbencher, described as a maverick, "supporting a range of seemingly perverse causes".^[13][14]

At the 1992 general election, Bottomley was again re-elected with a decreased vote share of 46% and a decreased majority of 1,666.^[15] Bottomley decided not to re-contest Eltham after major boundary changes, but sought nomination elsewhere. At the 1997 general election, Bottomley contested the newly formed constituency of Worthing West, where he was elected with 46.1% of the vote and a majority of 7,713.^[16]

Bottomley was re-elected as MP for Worthing West at the 2001 general election with an increased vote share of 47.5% and an increased majority of 9,037.^[17] He was again re-elected at the 2005 general election with an increased vote share of 47.6% and an increased majority of 9,379.^[18][19]

In 2009, Bottomley was the vice-chairman of the All Party Parliamentary Flag Group.^[20] In 2011, he was in more Parliamentary groups than any other MP.^[21] He is vice-chairman of All-Party United Nations Group and vice-chairman of All-Party Parliamentary Group (APPG) for Transport Safety.^[22]

At the 2010 general election, Bottomley was again re-elected with an increased vote share of 51.7% and an increased majority of 11,729.^[23][24]He was again re-elected at the 2015 general election with a decreased vote share of 51.5% and an increased majority of 16,855.^[25][26]

Before the 2016 referendum, Bottomley was in favour of the United Kingdom remaining in the European Union.^[27]

Bottomley has been a supporter of British pensioners living overseas, mainly in Commonwealth countries (47 out of 54) who have had their British state pensions frozen at the rates at which they were first paid or as at the dates of migration. British pensioners living in the remaining seven Commonwealth countries and those living in a number of non-Commonwealth countries have their British state pensions uprated each year, just as if they were living in the UK.^[28]

Bottomley was again re-elected at the snap 2017 general election, with an increased vote share of 55.4% and a decreased majority of 12,090.^[29][30]

An advocate for reducing the voting age to 16, Bottomley is a co-founder and Vice Chair of the APPG on Votes at 16 and a supporter of the Votes at 16 campaign.^{[31][32][33][34]}

Bottomley is co-chair to the APPG on Haemophilia and Contaminated Blood^[35] and campaigns to get justice for those affected by the tainted blood scandal.^[36] During a debate in Parliament on 24 November 2016, he urged Prime Minister Theresa May to look at the issue.^[37][38] Bottomley was again re-elected at the 2019 general election, with an increased vote share of 55.8% and an increased majority of 14,823,^[39] becoming the longest continuous-serving MP and thus Father of the House. The last two remaining MPs who had served continuously since the 1970 general election left Parliament in 2019: Kenneth Clarke, the previous Father, retired and Dennis Skinner lost re-election.