Cardiff South and Penarth
Borough constituency for theHouse of Commons
Interactive map of boundaries from 2024
Boundary of Cardiff South and Penarth in Wales
Preserved county	South Glamorgan
Population	107,455 (2011 census)[1]
Electorate	72,269 (March 2020)[2]
Current constituency
Created	1983
Member of Parliament	Stephen Doughty (Labour Co-op)
Seats	One
Created from	Cardiff South East & parts ofBarry andMonmouth[3]
Overlaps
Senedd	Cardiff South and Penarth,South Wales Central

Cardiff South and Penarth (Welsh:De Caerdydd a Phenarth) is a constituency^{[n 1]} created in 1983 represented in theHouse of Commons of theUK Parliament since2012 byStephen Doughty, aLabour Co-opMP, who has served asMinister of State for Europe, North America and Overseas Territories since July 2024.^[4][5]

The constituency retained its name, but with altered boundaries, as part of the2023 review of Westminster constituencies and under theJune 2023 final recommendations of theBoundary Commission for Wales for the2024 general election.^[6]

Map of boundaries 2010–2024

1983–2010: TheCity of Cardiff wards ofButetown,Grangetown,Llanrumney,Rumney,Splott, andTrowbridge; and theBorough of Vale of Glamorgan wards of Alexandra (becamePlymouth andSt Augustine's from 2004),Cornerswell,Llandough, andStanwell.

2010–2024: As above with the addition ofSully from theVale of Glamorgan seat.

2024–present: The City and County of Cardiff wards of Butetown, Cathays, Grangetown, and Splott; and the County Borough of the Vale of Glamorgan wards Cornerswell, Dinas Powys, Llandough, Plymouth, St Augustine's, Stanwell, and Sully.^[7]

The seat gainedCathays from the abolishedCardiff Central constituency, andDinas Powys from theVale of Glamorgan constituency,^[8] offset by the loss of Llanrumney, Rumney, and Trowbridge to the newCardiff East constituency.^[9]

Prior to 1983 Penarth had been part of the abolishedBarry constituency, represented by the Conservative backbencher SirRaymond Gower. Most of the electorate of the new constituency had previously fallen into the abolished seat ofCardiff South East, represented by former Prime Minister,James Callaghan.

Cardiff South and Penarth has had three MPs since its creation, containing some very safe Labour wards from Cardiff such asButetown,Grangetown andSplott, and several wards from the neighbouring borough of theVale of Glamorgan, withPenarth mostly favourable to Labour, but with some areas such asPlymouth andSully in the southern end of the seat where the Conservatives attracted more support. The first, elected at the1983 general election, was the formerLabourPrime MinisterJames Callaghan, who secured the seat with a 5.4% majority overConservativeDavid Tredinnick. Callaghan had immediately prior to the dissolution of Parliament, representedCardiff South East. Callaghan first became an MP at the1945 general election, forCardiff South.

The second MP wasAlun Michael (Labour andCo-operative Party) who served 25 years from1987 before choosing to stand down in 2012. Michael's affiliation with theCo-operative Party did not appear on ballot papers at the2010 general election because theElectoral Commission ruled that any joint candidates who wanted the names of both their parties included on the ballot paper could not also display the Labour red rose logo.^[10] Michael opted to drop the reference to theCo-operative Party but after the election denounced the ruling as "an outrageous piece of incompetence by the Electoral Commission".^[11] Michael briefly becameSecretary of State for Wales in 1998. Michael held the seat at the 2010 general election with a majority of 10.6% following a 6% swing to the Conservative candidate.^[12]

In 2012, Michael was selected by the Labour and Co-operative Parties as their candidate for the election of aPolice and Crime Commissioner for theSouth Wales Police force area and announced he would bestanding down from Parliament.^[13][14]

At a by-election held on 15 November 2012, Labour's decline was reversed coupled with very low turnout (down 38.2% on the previous election). Labour's Stephen Doughty succeeded Alun Michael winning 47.3% of the overall vote. This was an increase (in share-of-the-vote terms) on Michael's 2010 performance. However, in terms of actual votes cast (9,193 compared with 17,262 in 2010), it was Labour's lowest in this constituency. The 2015 result gave the seat the 83rd-smallest majority of Labour's 232 seats by percentage of majority.^[15] Labour's result in2017 saw them secure their largest ever margin in the constituency in terms of raw votes.

Five parties' candidates achieved more than thedeposit-retaining threshold of 5% of the vote in 2015. The second-placed candidate has been a Conservative candidate since the seat was formed. The closest result was in 1983, when Callaghan won by 5.5% of the vote.

Turnout at general elections has ranged between 77.2% in1992 and 56.2% in2005.

Of the 135 rejected ballots:

• 63 were either unmarked or it was uncertain who the vote was for.^[33]
• 69 voted for more than one candidate.^[33]
• 3 had writing or a mark by which the voter could be identified.^[33]

Of the 121 rejected ballots:

• 82 were either unmarked or it was uncertain who the vote was for.^[35]
• 35 voted for more than one candidate.^[35]
• 4 had writing or a mark by which the voter could be identified.^[35]

Of the 107 rejected ballots:

• 76 were either unmarked or it was uncertain who the vote was for.^[42]
• 29 voted for more than one candidate.^[42]
• 2 had writing or a mark by which the voter could be identified.^[42]

Of the 160 rejected ballots:

• 132 were either unmarked or it was uncertain who the vote was for.^[49]
• 27 voted for more than one candidate.^[49]
• 1 had writing or mark by which the voter could be identified.^[49]

• Cardiff South and Penarth (Senedd constituency)
• List of parliamentary constituencies in South Glamorgan
• List of UK Parliament constituencies in Wales

• nomis Constituency Profile for Cardiff South and Penarth – presenting data from the ONS annual population survey and other official statistics.
• Politics Resources (Election results from 1922 onwards)
• Electoral Calculus (Election results from 1955 onwards)
• 2017 Election House of Commons Library 2017 Election report
• A Vision Of Britain Through Time (Constituency elector numbers)
• "Results: Cardiff South & Penarth".BBC News: Election 2005.BBC News. 6 May 2005. Retrieved25 May 2006.
• "News Release – South Glamorgan"(PDF).Boundary Commission for Wales. 10 November 2004. Archived fromthe original(PDF) on 25 December 2004. Retrieved25 May 2006.
• "Aristotle: Cardiff South and Penarth".The Guardian. London. 8 May 2004. Archived fromthe original on 24 March 2007. Retrieved25 May 2006.
• Cardiff South and Penarth UK Parliament constituency (boundaries April 1997 – April 2010) atMapIt UK
• Cardiff South and Penarth UK Parliament constituency (boundaries April 2010 – May 2024) atMapIt UK
• Cardiff South and Penarth UK Parliament constituency (boundaries from June 2024) atMapIt UK

51°28′08″N3°07′37″W / 51.469°N 3.127°W /51.469; -3.127

• Constituencies of the Parliament of the United Kingdom established in 1983
• Constituencies of Cardiff
• Parliamentary constituencies in South Wales
• Politics of Penarth

• Wikipedia articles incorporating an LRPP-MP template with two unnamed parameters
• Webarchive template wayback links
• All articles with dead external links
• Articles with dead external links from November 2023
• Articles with permanently dead external links
• Pages using gadget WikiMiniAtlas
• Articles with short description
• Short description is different from Wikidata
• Use British English from November 2022
• All Wikipedia articles written in British English
• Use dmy dates from May 2022
• Articles containing Welsh-language text
• Coordinates on Wikidata
• Pages using the Kartographer extension