Making social science accessible

16 Apr 2021

Politics and Society

Why is 6 May a big election day?

Outside a general election or a nationwide referendum, the May 2021 elections constitute an electoral event unprecedented in scale in the United Kingdom. The postponement of last year’s elections due to Covid-19 has merged two busy years of devolved and local elections.

As a result, every eligible voter in England, Wales and Scotland will be able to go to the polling station and cast a ballot on ‘Super Thursday’.

In the May 2021 elections, voters will be electing 129 members of the Scottish Parliament; the 60 members of the Welsh Senedd; eight metro mayors, and a further five city mayoralties; nearly 5,000 local council seats in England; elections for the 25 members of the London Assembly; and 40 police and crime commissioners in England and Wales. There is also a by-election in the Labour seat of Hartlepool.

This article explains what is at stake in each of the nations in the UK (apart from in Northern Ireland, where no elections are being held), who will be voting and how each of these elections works.

The scale of the poll means that people will be keen to understand the wider implications for British politics: what it means for the national standing of the parties, and arguments about the future of the United Kingdom. We also set out the likely implications of different results.


Voters in England face an array of ballots, depending on where they live, for local councillors, combined authority and metro mayors, including the Mayor of London, and outside London for Police and Crime Commissioners (PCCs).



Local councils

There are six types of local authority in England: county councils, district councils, unitary authorities, metropolitan districts, London boroughs and town/parish councils. In total, around 30% of English council seats – nearly 5,000 – are up for election.

In some places, there is a two-level system of county councils and district councils, in others there are unitary councils.

County councils cover the whole of the county and provide the majority of public services in their particular area. County councils are responsible for services such as: education, roads, transport planning, social care, libraries and waste disposal. In May, 21 of the 24 English county councils are up for election, and nearly all these councils have a Conservative majority (Nottinghamshire and Oxfordshire, where the Conservatives are the largest party, being the exceptions).

District councils (which can also be called city or borough councils, if they are in a city) or town councils are the layer below county councils, and operate more localised services: such as housing and rubbish collection. Around a third of district councils will hold elections: 46 electing a third of the council, six electing half the district council and a further seven where all seats will be filled in the May 2021 elections.

In unitary authorities, one council covers the whole area. There are 58 unitary authorities.

In 30 of these there are no council elections (though voters will still get to vote for their PCC, as explained below).

In 15 unitary authorities, one third of the councillors will be elected, and in another 13 all the councillors will be elected at once. There is a wide geographic spread and a mix of party running these councils now.

Metropolitan districts are single district authorities that operate in a similar way to unitary authorities. Three metropolitan boroughs – Salford, Doncaster and Rotherham – are holding ‘all in’ elections where all council seats will be up for grabs, a further 32 will see a third of seats voted on. Nearly all of these councils are currently held by the Labour Party.

London Assembly

London boroughs are not being contested, but the 25 members of the Greater London Assembly are all up for re-election. This is an extra layer of governance unique to London.

The London Assembly consists of 25 members, whose job it is to hold the Mayor of London accountable across the areas over which he has direct responsibility: including Transport for London, the Metropolitan Police, the London Fire Brigade and strategic plans for London. It has the power to amend budgets, and make policy proposals to the Mayor.

Mayoralties in England

More than 20 million people in England will be choosing city and city-region mayors in Greater London, Greater Manchester, the West Midlands, the Liverpool City Region, Tees Valley, Cambridgeshire and Peterborough, and the West of England. The first metro mayor of West Yorkshire will also be elected.

Exactly what these mayors can do varies from place to place. Most have powers over housing, transport and local industrial powers that were previously held by local authorities. Some areas – Greater Manchester and London, as well as West Yorkshire following these elections – have additional devolved powers, over areas such as policing and health and social care budgets.

There are also an additional five single-authority mayoralties up for election: Bristol, Doncaster, Liverpool, North Tyneside and Salford. These are directly elected mayors with fewer formal powers, but who share with city-region mayors a key role in acting as ambassadors for their patch. Marvin Rees, for example, became a prominent national voice for Bristol during the debate over the removal of the Colston statue and in speaking out about  the ‘Kill the Bill’ protests.

Police and Crime Commissioners

PCCs, created in 2012, are responsible for policing in their jurisdiction. Apart from in Greater Manchester and Greater London (and soon West Yorkshire), where the mayor is the directly elected official responsible for policing, every voter in England and Wales elects a PCC. All of these positions are up for re-election.

Who will be voting?

In the May 2021 elections in England, every eligible voter over 18 can vote. This includes resident EU citizens, qualifying commonwealth citizens and citizens of the Republic of Ireland living in England.

Turnout for council elections varies at between 30-35%. The London mayoral and London Assembly elections had a turnout of 45% in 2016. The metro mayor elections had a turnout of between 21% (Tees Valley) and 30% (West of England) in 2017. Police and Crime Commissioner elections have seen some very low turnouts (an average of 15% in 2012), but are likely to be bolstered in many areas by other elections taking place.

How do the elections work?

Local councils

Councillors will be elected using first-past-the-post, meaning that the candidate with the most votes in a ward is elected.

In councils wards where all the seats are up for grabs, bloc voting is in operation. This means voters can vote for more than one candidate from the same party – but all are still elected on a first-past-the-post basis.

Mayoralties in England

All city-region mayors are elected using the supplementary vote system. Voters can vote for their first and second choice candidate – putting an X in the first choice column and an X in the second-choice column.

If no candidate obtains more than 50% of the first choice votes, all candidates except for those in first and second place are eliminated. The ballot papers showing a first preference for one of the eliminated candidates are checked for their second preference. Any second preference votes for the remaining two candidates are then added to their first preference votes and the candidate with the most votes is elected.

London Assembly

Elections to the London Assembly operate under the Additional Member System also used in the devolved elections to the Scottish Parliament and the Welsh Senedd. There are 14 geographical super-constituencies each electing one member, with a further 11 members elected from a proportional party list distributed to make the final distribution of parties more proportional.

Police and Crime Commissioners

PCCs are elected using the supplementary vote system used for metro mayors.

What should we look out for in the results?

Local councils

The local council contests at stake can also be bracketed into three groups: the 93 contests where a third of the council seats are at stake; the six councils where half the seats are up for grabs; and the 44 councils where every seat will be up for election.

It is difficult to interpret a national picture from council elections in England, as which areas are holding elections defines which party is most likely to win. The political scientists Colin Rallings and Michael Thrasher estimate national equivalent vote shares after local elections, contextualising the individual contests to create a national picture. These numbers play a key role in interpreting the national ‘winner’ of these localised contests.

In these local elections, there will be a mixture of council seats last fought in 2016 and 2017. In 2016, Rallings and Thrasher estimated Corbyn’s Labour and Cameron’s Conservatives were neck and neck. In 2017, they registered 39% for the Conservatives and 28% for Labour.

What this means is that in the places last fought for in 2017 – for example all English county councils – the Conservative party did particularly well, pushing eight from ‘no overall control’ into the Conservative column and removing Labour majorities in the only two places where Labour held a majority (Nottingham and Derby). The contest for Nottingham county council – currently 31 Conservatives, 23 Labour and a set of independents – is a useful bellwether, a close contest where all seats are up for grabs.

Although metropolitan councils are broadly Labour strongholds, there are some contests that will provide a useful test for the stability of the ‘Red Wall’. The metropolitan councils of Rotherham and Doncaster – where Labour hold a majority, but where the Conservatives have made advances since these elections were last fought – will provide a key test of how the changes we have seen in British politics since 2016 have reshaped politics.

Mayoralties in England

While some of the city-region contests appear foregone conclusions (Andy Burnham, for example, is 1/66 on to be re-elected), others will be much more competitive.

In the West Midlands the incumbent Andy Street won by 50.4 to 49.6% in 2017 – a year where the Conservatives did particularly well nationally. While he is expected to receive an incumbency boost, the Labour challenger Liam Byrne could win. The West of England contest is also expected to be a tight race.

The contest in Tees Valley – won unexpectedly by the Conservative candidate in 2017 by 51% to 49% – will be seen as a test of whether Keir Starmer has made any progress in regaining ground lost in recent years to the Conservative Party in the North East.

London Assembly

It is likely that Labour will dominate these elections, and current polling suggests that the possibility of Sadiq Khan achieving over 50% in first round votes for the mayoralty could in turn mean an absolute majority for Labour in the Assembly.


In Scotland, voters will be voting to determine the make-up of the Scottish Parliament.

The make-up of the Scottish Parliament decides who runs the Scottish Government, as well as being the legislative body that scrutinises that Government. The Scottish Parliament runs a broad range of devolved policy areas, including education, the environment, agriculture, health (including management of Covid-19), and deciding the rates of some taxes – totalling 31% of tax revenue in Scotland.

Questions of the constitution and further devolution, including whether or not another independence referendum will be held, are decisions for Westminster. However, it is widely thought that a majority for the Scottish National Party (SNP), or a majority including the pro-independence Green Party and the newly-formed Alba, would increase the pressure for an independence vote.

There will not be any mayoral or PCC elections, and only a handful of council by-elections for individual seats.

Who will be voting?

In these elections, every eligible voter over 16 can vote. This includes all legally resident foreign nationals and, unlike other UK elections, prisoners serving a sentence of 12 months or less. Turnout for the Scottish Parliament elections in 2016 was 55.8%.

How do the elections work?

The Additional Member System is used to elect Members of the Scottish Parliament (MSPs). Voters are given two ballot papers – one with a list of candidates for their local representative, and another a list of parties for the national list. 73 MSPs are elected using the constituency system, and a further 56 from the second ballot list.

Constituencies are decided first, under the usual first-past-the-post system. The regional list system is then used to make the number of MSPs for each party more equally match the number of votes each party received.

Some parties – for example the Green Party and Alba – only contest the regional list.

What should we look out for in the results?

It is expected that the SNP will perform most strongly on the constituency section (where polls show the part at around 50%) and will also come top in the regional list system (where the party polls around 40%). This is principally due to less pro-independence competition on the constituency ballot.

Given the SNP will win a disproportionate number of seats under the first-past-the-post constituency system, it is unlikely they will pick up many list seats – leading to arguments over how a ‘supermajority’ for independence could be created by voters opting backing another pro-independence party.

Prior to the creation of Alba, pollster Sir John Curtice described the chances of an SNP majority in these elections as a ‘50-50 shot’. The new party creates additional uncertainty about whether the pro-independence vote will be effectively distributed.

This contest will also provide an early electoral test for the new Scottish Labour leader Anas Sarwar and Conservative leader Douglas Ross.


In Wales, voters will be deciding on the make-up of the 60-seat Welsh Senedd.

The Senedd has devolved responsibility over health (including the management of Covid-19), agriculture, culture, the environment, transport, business, economic development, and social services. Devolved taxes and local property taxes currently make up 20% of the tax revenue in Wales – and the Welsh Government now as increased tax and borrowing powers including, since 2019, the power to vary income tax by 10p in each band.

The make-up of the Senedd then determines who runs the Welsh Government, and the legislature scrutinises that Government.

There will also be four PCCs up for election in Wales in the May 2021 elections.

Who will be voting?

For the first time, 16 and 17- year olds will be able to vote in elections to the Welsh Senedd. All legally resident foreign nationals will be able to vote. In 2016, turnout was 45.3%.

How do the elections work?

As in Scotland, the Additional Member System is used to elect members of the Welsh Senedd. There are 40 constituency members elected, and a further 20 elected from the regional list.

Some parties, like the Abolish the Welsh Assembly Party and the Greens, will be running in some but not all the constituency-level contests.

The PCCs, as in England, will be elected using the supplementary vote system.

What should we look out for in the results?

The crux of the electoral battle in Wales is whether Labour will be able to hold on to enough seats to govern without the support of other parties. In 2007, the ‘One Wales’ Labour-Plaid coalition formed a government. In 2016, Labour was able to rely on the support of the single Liberal Democrat member for a majority.

While it remains overwhelmingly likely that Labour will remain the largest party in Wales, recent polling has seen a surge in support for the Conservative Party in Wales. Key to the contest is the extent to which Labour First Minister Mark Drakeford and the Welsh Government’s widely-supported handling of the pandemic boosts support for Labour.

Key to interpretations of the results will be the extent to which Plaid Cymru’s performance matches expectations, and subsequently how that affects government formation following the poll.

The performance of parties on the right, Abolish the Assembly and Reform UK, will also be one to watch given the previous performance of UKIP in devolved elections in Wales. 

Northern Ireland

There are no elections taking place in Northern Ireland.

By Dr Alan Wager, Research Associate at The UK in a Changing Europe


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