2024 general election: Marginality

Georgina Sturge

A large rise in marginal seats

The 2024 general election produced a large rise in the number of very marginal seats (where the elected candidate won with only a small majority), compared with the most recent previous elections.

Nearly one in every five seats – 115 in total – was won by a margin of 5% or less of total votes cast. There were 48 more seats in this marginal category than at the 2019 general election.

Correspondingly, the proportion of very safe seats fell. Just five seats were won with a majority of over 50% of votes cast at this election, down from 37 in 2019 and 35 in 2017. The chart below illustrates these trends by grouping seats into 5% majority bands for the last five general elections.

The pattern of marginality at the 2024 election was more like the pattern in 2010 than that of any election since. In 2010, 31% of seats were won by a margin of less than 10%, which was similar to the 34% of seats won by this margin in 2024. Similarly, in 2010 and 2024, only between 1% and 2% of seats were won by a margin of 50% or more, a figure which had ranged between 6% and 10% at the general elections in between.

Which were the most marginal seats?

The table below lists the 20 most marginal seats in percentage terms. In all these seats, the winning margin was less than 2% (there were 46 seats in total which had a margin within this range). The full list of seats by majority can be viewed on the Commons Library’s election results website.


The most marginal seats
Rank	Constituency	Country/region	Winner/result	Second party	Majority (%)	Majority (votes)
1	Hendon	London	Lab gain from Con	Con	0.04%	15
2	Poole	South West	Lab gain from Con	Con	0.04%	18
3	Basildon and Billericay	East of England	Con hold	Lab	0.05%	20
4	North West Cambridgeshire	East of England	Lab gain from Con	Con	0.09%	39
5	Central Devon	South West	Con hold	Lab	0.11%	61
6	Havant	South East	Con hold	Lab	0.22%	92
7	Exmouth and Exeter East	South West	Con hold	Lab	0.24%	121
8	South Basildon and East Thurrock	East of England	RUK gain from Con	Lab	0.25%	98
9	Beverley and Holderness	Yorkshire and The Humber	Con hold	Lab	0.28%	124
10	Peterborough	East of England	Lab gain from Con	Con	0.28%	118
11	Chelsea and Fulham	London	Lab gain from Con	Con	0.32%	152
12	Blackburn	North West	Ind gain from Lab	Lab	0.34%	132
13	East Londonderry	Northern Ireland	DUP hold	SF	0.43%	179
14	Middlesbrough South and East Cleveland	North East	Lab gain from Con	Con	0.56%	214
15	Forest of Dean	South West	Lab gain from Con	Con	0.58%	278
16	Bromley and Biggin Hill	London	Con hold	Lab	0.65%	302
17	Derbyshire Dales	East Midlands	Lab gain from Con	Con	0.68%	350
18	Sittingbourne and Sheppey	South East	Lab gain from Con	Con	0.87%	355
19	Ely and East Cambridgeshire	East of England	LD gain from Con	Con	0.95%	495
20	North Antrim	Northern Ireland	TUV gain from DUP	DUP	1.09%	450

In 2019, all but seven of the 46 most marginal seats in the 2024 election were won by a relatively high margin of over 20%, and over half (25 seats) had been won by more than 30% of the vote. The biggest percentage point decline in margin was in South West Norfolk, in which the Labour Party overturned a Conservative majority of 50.3% (24,180 votes) in 2019. Labour won in 2024 with a majority of 1.4% (630 votes), reflecting a large swing in the vote.

Thirty-three of the 40 most marginal seats in 2024 were seats which had been won by the Conservative Party in 2019. Of these, the Conservatives held 11 and lost 22. The tightest contest was in Hendon, London, which was a Labour gain from the Conservatives with a margin of just 0.04%, or 15 votes.

The map below shows the number of seats at the 2024 general election with a majority under 5%, by winning party.

Which were the least marginal (safest) seats?

The seat with the biggest margin was Chorley, where Sir Lindsay Hoyle stood as the Speaker seeking re-election. Conventionally, the Speaker’s seat is not contested by the largest parties when the Speaker runs for re-election. The table below lists the 20 safest seats plus the Speaker’s seat, ranked by the winning margin as a percentage of the total vote.


The safest seats
Rank	Constituency	Country/region	Winner/result	Second party	Majority (%)	Majority (votes)
1	Chorley	North West	Spk hold	Green	60.58%	20,575
2	Bootle	North West	Lab hold	RUK	56.54%	21,983
3	Liverpool Walton	North West	Lab hold	RUK	54.89%	20,245
4	Liverpool West Derby	North West	Lab hold	RUK	53.74%	20,423
5	Knowsley	North West	Lab hold	RUK	50.82%	18,319
6	Liverpool Garston	North West	Lab hold	RUK	47.87%	20,104
7	Liverpool Riverside	North West	Lab hold	Green	45.68%	14,793
8	Lewisham East	London	Lab hold	Green	44.47%	18,073
9	York Central	Yorkshire and The Humber	Lab hold	Con	44.21%	19,154
10	Hornsey and Friern Barnet	London	Lab hold	Green	44.15%	21,475
11	Westmorland and Lonsdale	North West	LD gain from Con	Con	43.35%	21,472
12	Widnes and Halewood	North West	Lab hold	RUK	43.09%	16,425
13	Greenwich and Woolwich	London	Lab hold	Green	42.99%	18,366
14	Clapham and Brixton Hill	London	Lab hold	LD	42.13%	18,005
15	Wallasey	North West	Lab hold	RUK	42.10%	17,996
16	Nottingham East	East Midlands	Lab hold	Green	41.65%	15,162
17	Mitcham and Morden	London	Lab hold	Con	41.46%	18,761
18	Dulwich and West Norwood	London	Lab hold	Green	41.41%	18,789
19	Liverpool Wavertree	North West	Lab hold	Green	40.95%	16,304
20	Blaenau Gwent and Rhymney	Wales	Lab hold	PC	40.72%	12,183

After the Speaker’s seat, the 40 safest seats were won by between 36.8% and 56.5% of the vote. In all but one of these, the result was that the incumbent party held the seat.

In 34 of the 40 safest seats, the result was a Labour hold, with winning margins ranging from 36.8% to 56.5% of the vote. Most of the safest seats in 2024 had not ranked among the safest in 2019. Notable exceptions were seven seats in Liverpool City Region, which appeared in the top 20 safest seats in 2019 and 2024.

The only seat on the list above which changed hands was Westmorland and Lonsdale. This was won by the Liberal Democrats in 2019.However, after the boundary changes, the notional 2019 results estimated that the seat would have voted Conservative in 2019 if the election had been held on 2024 boundaries (with a notional majority of 9.5%). In 2024 the Liberal Democrats won the seat on its new boundaries, with a majority of 43.4%.

Is there a relationship between turnout and marginality?

Overall, there was no relationship between turnout and the size of a winning margin. However, some patterns did emerge when looking at specific types of result. For example, in seats which were held by Labour, turnout was, on the whole, relatively low and the winning margin was relatively high.

The opposite was the case in seats won by the Conservative Party, where turnout was relatively high and winning margins tended to be low, at less than 10% on average. The 72 seats won by the Liberal Democrats, 64 of which were gains, all had higher than average turnout but winning margins were quite evenly spread, from 1.0% to 43.4%.

These patterns are shown in the chart below.

Sinn Féin was the party with the highest average margin across the seats it won, at 26.6%, and Traditional Unionist Voice the party with the lowest, at 1.1% in the one seat that it won. The average winning margin in Labour seats was 18.9%, while in Conservative seats it was 8.5%.

About the author: Georgina Sturge is a senior researcher in the Social and General Statistics section of the Commons Library.