Constituency profile

Mitcham and Morden

London · Borough constituency · Merton borough

Dame Siobhain McDonagh MP
Sitting MP

Dame Siobhain McDonagh

Labour

First elected May 1997

Current PollCheck projection

Region & type
London
Borough constituency, Merton council
Last 5 GE winners
LLLLL
Labour 5/5
EU referendum 2016
44.7% Leave
UK average 51.9%; -7.2pp below mean
Current outlook
Labour +27.2pp
vs Reform UK 17.9%
LondonRemain-leaningDiverse

About the Mitcham and Morden constituency

Mitcham and Morden is a borough constituency in London. The sitting MP is Dame Siobhain McDonagh (Labour), first elected in May 1997. At the 2024 general election, Labour won with 55.4% to 14.0% for the Conservatives, a majority of 18,761 votes on a 58.6% turnout. PollCheck's current projection, at the seven-poll average, has Labour on 45.1% and Reform UK on 17.9%, a margin of 27.2 points.

Who lives in Mitcham and Morden? Constituency demographics

From the 2021 Census and 2016 EU referendum estimates. Constituency-level data on 2024 boundaries.

Leave vote 2016
44.7%
UK average ~52%
Degree or above
40.0%
UK average ~34%
No qualifications
18.1%
UK average ~18%
Owner-occupied
53.1%
UK average ~63%
Renting (social + private)
45.5%
UK average ~36%
Median age
36.9
UK median ~40
Age 65+
14.6%
UK average ~19%
Age 18-34
34.4%
UK average ~28%

How did Mitcham and Morden vote in 2024 and how would it vote now?

2024 vote shares from the HoC Library. Current projection is at the 7-poll average.

2024 general election

Lab hold · majority 18,761 votes (41.4pp) · turnout 58.6%

Current projection

If a general election were held today, at current poll average

Map of Mitcham and Morden

Switch between GE2024 ward winners (modelled estimates, ~4pp average error) and a demographic view from the 2021 Census. Hover any area for detail. How the map is built ›

Council layer (not Westminster)

Mitcham and Morden within Merton

Mitcham and Morden sits entirely within Merton Council. The figures below are from the council elections held on 7 May 2026. About this layer ›

Council overlap

CouncilShare of seatProjection
Merton
70 LSOAs
100%View projection ›

Most recent council ward results

Latest council winner per ward - May 2026 results where the council voted, otherwise the most recent available result. How this table is sourced ›

Ward GE2024 winner Latest council winner Shift since GE2024 Turnout
Cannon HillLabour 41.0%vs Conservative 21.2%May 2026 Lib Dem 35.5%vs Conservative 25.0%
Labour→Lib Dem
+19.9pp
-
Colliers WoodLabour 54.6%vs Green 15.9%May 2026 Labour 44.1%vs Green 21.4%
Labour share
-10.5pp
-
Cricket GreenLabour 58.4%vs Conservative 12.2%May 2026 Labour 52.6%vs Reform 16.3%
Labour share
-5.8pp
-
Figge's MarshLabour 61.0%vs Conservative 10.9%May 2026 Labour 55.9%vs Green 17.6%
Labour share
-5.2pp
-
GraveneyLabour 60.0%vs Conservative 11.6%May 2026 Labour 52.7%vs Green 23.1%
Labour share
-7.3pp
-
Lavender FieldsLabour 55.8%vs Conservative 12.2%May 2026 Labour 43.6%vs Green 21.0%
Labour share
-12.2pp
-
LongthorntonLabour 57.8%vs Conservative 13.0%May 2026 Labour 54.9%vs Green 14.8%
Labour share
-2.9pp
-
Lower MordenLabour 49.8%vs Conservative 22.9%May 2026 Labour 35.3%vs Reform 24.8%
Labour share
-14.5pp
-
Pollards HillLabour 60.7%vs Conservative 12.3%May 2026 Labour 60.4%vs Reform 15.6%
Labour share
-0.3pp
-
RavensburyLabour 57.0%vs Conservative 13.1%May 2026 Labour 43.6%vs Lib Dem 24.9%
Labour share
-13.4pp
-
St HelierLabour 54.6%vs Conservative 13.2%May 2026 Labour 39.0%vs Green 27.6%
Labour share
-15.7pp
-

Projection trajectory

PollCheck's projection for Mitcham and Morden at each of the last 60 GB polls. Hover the chart for the underlying poll details.

Who has won Mitcham and Morden at past general elections?

2024 and notional 2019 rows are on current boundaries; 2010-2017 rows are on the boundaries in force at the time. More on boundaries ›

Year Result MP Lab Con LD Right (Ref/UKIP) Green Other Majority Turnout
2010Lab holdSiobhain McDonagh56.4%25.2%11.9%2.0% UKIP0.9%3.6%13,66666.4%
2015Lab holdSiobhain McDonagh60.7%23.2%3.1%9.5% UKIP3.2%0.5%16,92265.9%-0.5
2017Lab holdSiobhain McDonagh68.7%24.2%3.1%2.2% UKIP1.3%0.5%21,37570.0%+4.1
2019notionalLabour winnerSiobhain McDonagh 2019 MP, pre-review boundary57.5%26.7%10.8%-2.2%2.8%15,87967.2%-2.8
2024Lab holdSiobhain McDonagh55.4%14.0%8.0%9.1% Ref10.2%3.2%18,76158.6%-8.6

Earlier years are on pre-2024 boundaries; comparable results on the new boundary will be added when sourced.

Constituencies most like Mitcham and Morden

Five seats with similar demographic profiles to Mitcham and Morden. Politics shown for context.

What would change this seat?

Move the sliders to set national vote shares. The per-seat projection updates live. Reset returns to the current 7-poll average.

Related

Sources

Every figure on this page is computed from the sources below. Read the full methodology ›

Show full source list
  • 2024 general election results · UK Parliament Election Results portal and House of Commons Library briefing CBP-10009.
  • Notional 2019 results on 2024 boundaries · UK Parliament Election Results portal. Recalculated by Parliament; carries assumptions about how 2019 voters would have distributed across the redrawn boundaries.
  • Historic general election results (2010-2017) · House of Commons Library historic results files (on the boundaries in force at the time).
  • Ward-level GE2024 estimates · Britain Elects / New Statesman - article by Ben Walker, underlying spreadsheet. Modelled from constituency totals; average ~4pp per-ward MoE.
  • May 2026 council ward results · Democracy Club via PollCheck's locals 2026 dataset.
  • Earlier council ward results (2014-2024) · DCLEAPIL v1.0 (Jason Leman, drawing on Andrew Teale's LEAP dataset and Democracy Club).
  • Demographics · ONS Census 2021 (England and Wales), aggregated to constituency level using the ONS LSOA21 -> PCON24 best-fit lookup.
  • EU referendum 2016 estimates · Constituency-level Leave vote estimates (Hanretty 2017 method).
  • MP details and Cabinet roles · UK Parliament Members API. MP photos are fetched live from the same source.
  • Boundary geometry and lookups · ONS Open Geography Portal (PCON24 boundaries, LSOA21 boundaries, LSOA21-WD24-LAD24 best-fit lookup).
  • Current projection and trajectory · PollCheck's demographic swingometer applied to the rolling 7-poll average from aggregated GB polls. Not a true MRP - vote-share movements are applied through per-constituency sensitivity multipliers derived from demographic regressions.

If you spot a data issue, please let us know.