Hertsmere
East of England · County constituency
About the Hertsmere constituency
Hertsmere is a county constituency in the East of England. The sitting MP is Sir Oliver Dowden (Conservative), first elected in May 2015. At the 2024 general election, the Conservatives won with 44.7% to 28.0% for Labour, a majority of 7,992 votes on a 65.3% turnout. PollCheck's current projection, at the seven-poll average, has the Conservatives on 35.9% and Reform UK on 26.6%, a margin of 9.3 points.
Who lives in Hertsmere? Constituency demographics
From the 2021 Census and 2016 EU referendum estimates. Constituency-level data on 2024 boundaries.
How did Hertsmere 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
Current projection
Map of Hertsmere
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 ›
Hertsmere within Hertsmere
Hertsmere sits almost entirely within Hertsmere Council. The figures below are from the council elections held on 7 May 2026. About this layer ›
Council overlap
| Council | Share of seat | Projection |
|---|---|---|
| Hertsmere | 95% | — |
| Welwyn Hatfield | 5% | View projection › |
Recent council by-elections
Council ward by-elections held inside this seat, most recent first. The result column shows which party won; the share column shows the top three parties’ vote shares on the day.
| Date | Ward | Result | Top 3 vote shares |
|---|---|---|---|
| 24 Jul 2025 | Borehamwood Brookmeadow | Con HOLD | Con 30% Ref 24% Other 23% |
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 |
|---|---|---|---|---|
| Aldenham East | Conservative 56.2%vs Labour 18.4% | 2023 Conservative 65.5%vs Lib Dem 22.0% | - | 37.6% |
| Aldenham West | Conservative 53.8%vs Labour 20.3% | 2023 Conservative 69.7%vs Labour 15.4% | - | 31.5% |
| Bentley Heath & The Royds | Conservative 42.1%vs Labour 30.9% | 2023 Labour 47.0%vs Conservative 46.8% | - | 37.6% |
| Borehamwood Brookmeadow | Conservative 38.3%vs Labour 33.1% | 2023 Labour 50.9%vs Conservative 45.0% | - | 31.9% |
| Borehamwood Cowley Hill | Labour 39.9%vs Conservative 33.4% | 2023 Labour 66.2%vs Conservative 25.8% | - | 25.6% |
| Borehamwood Hillside | Conservative 42.7%vs Labour 33.1% | 2023 Labour 46.8%vs Conservative 44.9% | - | 35.8% |
| Borehamwood Kenilworth | Labour 35.6%vs Conservative 35.3% | 2023 Labour 62.5%vs Conservative 32.6% | - | 28.9% |
| Bushey Heath | Conservative 50.8%vs Labour 20.1% | 2023 Conservative 63.9%vs Lib Dem 28.6% | - | 34.7% |
| Bushey Park | Conservative 47.6%vs Labour 21.3% | 2023 Lib Dem 52.7%vs Conservative 40.0% | - | 40.3% |
| Bushey St James | Conservative 42.1%vs Labour 23.8% | 2023 Lib Dem 55.6%vs Conservative 33.7% | - | 33.6% |
| Elstree | Conservative 50.7%vs Labour 22.5% | 2023 Conservative 69.9%vs Labour 22.2% | - | 32.2% |
| Northaw and Cuffley | Conservative 54.7%vs Labour 20.1% | May 2026 Conservative 52.5%vs Reform 30.8% | Conservative share -2.1pp | 47.5% |
| Potters Bar Furzefield | Conservative 41.8%vs Labour 36.7% | 2023 Labour 59.4%vs Conservative 34.5% | - | 35.0% |
| Potters Bar Oakmere | Conservative 39.2%vs Labour 32.5% | 2023 Conservative 47.9%vs Labour 47.0% | - | 32.5% |
| Potters Bar Parkfield | Conservative 47.2%vs Labour 26.2% | 2023 Conservative 57.7%vs Labour 30.9% | - | 41.1% |
| Shenley | Conservative 46.8%vs Labour 27.2% | 2023 Conservative 43.1%vs Labour 29.4% | - | 40.8% |
Projection trajectory
PollCheck's projection for Hertsmere at each of the last 60 GB polls. Hover the chart for the underlying poll details.
Who has won Hertsmere 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 | Majority | Turnout |
|---|---|---|---|---|---|---|---|
| 2010 | Con hold | James Clappison | 18.8% | 56.0% | 17.4% | 17,605 | 64.7% |
| 2015 | Con hold | Oliver Dowden | 22.4% | 59.3% | 5.5% | 18,461 | 67.9%+3.2 |
| 2017 | Con hold | Oliver Dowden | 28.7% | 61.1% | 5.3% | 16,951 | 71.0%+3.1 |
| 2019notional | Conservative winner | Oliver Dowden 2019 MP, pre-review boundary | 21.1% | 64.9% | 10.9% | 22,980 | 71.7%+0.7 |
| 2024 | Con hold | Oliver Dowden | 28.0% | 44.7% | 7.7% | 7,992 | 65.3%-6.4 |
Earlier years are on pre-2024 boundaries; comparable results on the new boundary will be added when sourced.
Constituencies most like Hertsmere
Five seats with similar demographic profiles to Hertsmere. Politics shown for context.
- ↑Graduate39.3 / 36.2vs 33.7
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.