Electoral registration in Great Britain in 2021


About this report

This report looks at how the 2021 canvass in Great Britain was run and considers the ongoing impact on the electoral registers of the changes to the annual canvass process introduced in 2020.

The 2021 canvass was the second using the new processes introduced in 2020. These changes involve comparing the registers with other public data in order to give EROs information they can use to target their resources at households where residents’ details are most likely to have changed.

While we cannot yet draw conclusions on the impact of the new process on the accuracy and completeness of the registers, our analysis of available data suggests potential issues with the effectiveness of the reformed canvass in keeping pace with population movement:

  • The data matching process and/or the lag between matching and canvassing means some households are being allocated to the ‘wrong’ route – nearly a fifth of responses from households allocated to Route 1 (where no change in household composition was expected) reported significant changes to electors’ details. 
  • Necessary changes to electors’ details may not be reflected on the registers – 2.4 million households, one third of those allocated to Route 2 (where a change in household composition was expected), did not respond to the canvass. 
  • The reduction in the frequency of communication with Route 1 households may be contributing to the under-registration of attainers (those who will soon reach voting age) – the decline in the number of registered attainers, which began following the introduction of individual electoral registration (IER) in 2014, continued in 2021. The number of registered attainers dropped by 28.7% relative to 2020.

While we know that new registration applications are most readily driven by large scale electoral events, it is nevertheless important that the canvass and other year-round registration activity supports accurate and complete registers. This can help to reduce the large volumes of registration applications received immediately in advance of major polls, when Electoral Registration Officers’ (EROs) staff capacity is already stretched.

Our research studies into the accuracy and completeness of the registers are the definitive assessments of their overall quality. The next study, planned for the December 2022 registers, will allow us to fully assess the overall impact of the new canvass processes.

Over the next year we will continue to support and challenge EROs using the performance standards framework, and work with them to ensure we all make full use of the data that is available. This should help to provide a better understanding of the impact of particular practices within the current framework and support us with identifying and sharing good practice.

We also continue to recommend that the electoral registration system in Great Britain should be further modernised, to provide the best possible opportunity for ensuring that as many people as possible are correctly registered. This should include better use of public data, for example from other government services, to make registration easier for voters, and a more joined-up electoral registration system to reduce duplicate registrations and encourage registration all year round.  

Other register statistics

Variations in response rate

Major and minor changes per route

Major and minor changes per route

The nature of the responses received is also important. Responding households can record a major change (e.g. reporting that a potential new elector is resident), a minor change (e.g. amending the name of an existing elector) or no change (i.e. confirming the existing details of household members). Understanding the distribution of these changes can tell us about the accuracy of the data matching.

Of the 9 million responses received across all routes, 2.7 million households reported a major change (30.4%). Table 10 shows how these major changes were distributed across the three routes. The pattern is broadly in line with 2020. 

Table 10. Distribution of major changes across routes

  Number of major changes % of major changes across all routes
Route 1 830,743 30.4%
Route 2 1,856,309 67.8%
Route 3 49,339 1.8%
Total 2,736,391 100.0%

The highest proportion of major changes were reported by Route 2 households – i.e., those identified during the data matching step as the households most likely to report changes to residents’ registration details. However, as in 2020, nearly a third of the major changes reported relate to Route 1 households, where the DWP and/or local data had indicated no change was likely to be needed.

As in 2020, of all the households allocated to Route 1 (21.7 million) the proportion reporting a major change (830,743) is small (3.8%). However, as Figure 1 below shows, of those that did respond, a fifth reported a major change. Importantly for the quality of the registers, it is also unlikely that all of the Route 1 households that needed to report a major change have done so – particularly as they would have received limited contact from the ERO.

We do not have comparative data on the number of major changes reported by households during the canvasses preceding the reforms. It is therefore not clear to what extent the 2020 and 2021 canvasses are out of line with historic figures. However, it is clear that either the data matching process does not accurately identify all properties where changes will be needed and/or there is an impact from the lag time between the matching and the canvassing taking place.

Figure 1. Percentage of responding households in Routes 1 and 2 who reported major / minor / no change (data collected from 4/5 LAs where a revised data specification was implemented)1

Percentage of responding households in Routes 1 and 2 who reported major / minor / no change

As part of our work with EROs throughout the 2021 canvass, we have sought to understand the potential reasons for the proportion of changes reported for route 1 households. Many of those we spoke to highlighted potential reasons such as house moves within areas, marriages, attainers and deaths. It could also be a product of data accuracy, for example, with records used for matching not being up to date. We will continue to build on this over the 2022 canvass, to develop a deeper understanding of the data and how the process is working in practice.

Additions and deletions

Canvassing households does not directly result in new registrations. When a household reports that a potential new elector is resident, that individual still needs to submit an application to be added to the register. Where a household reports that electors need to be removed from the registers, a second piece of evidence (e.g. locally held data) would be needed before the ERO could confirm the deletion.

Entries need to be added to, and deleted from, the registers for several reasons including migration, home movement and deaths. The level of these additions and deletions provides insight into whether registration activity is keeping pace with population change. As population mobility varies across the country, so does the scale of the challenge faced by EROs. 

As in 2020, the distribution of additions and deletions across the routes is largely as expected, with Route 2 households accounting for the highest proportion of changes (see Table 11). However, as with the household major changes, more than a third of both additions and deletions came from households whose composition was assumed to be unchanged following the data matching. Again, this suggests either a degree of inaccuracy in the allocation of households to routes or an impact from population movement between matching and canvassing.  

Table 11. Percentage of additions and deletions per route 

  Route 1 Route 2 Route 3
Additions 37.1% 59.6% 3.4%
Deletions 39.4% 57.3% 3.3%

This data suggests that at least some population change is not being picked up by the registers. However we cannot draw clear conclusions on the overall impact – partly because of the variable impact of electoral events outside the canvass.

Table 12 below shows the levels of additions and deletions in recent years (for the full year, not just the canvass). Both 2020 and 2021 have recorded lower figures than many previous years. However, it is usual to see higher levels, of additions in particular, in years with significant UK-wide electoral events (such as UK general elections and the EU referendum). The lower figures in 2020 may relate directly to the effects of the pandemic – both on EROs’ ability to canvass and through depressing levels of population movement. 

Table 12. Percentage of additions and deletions 2010-21

Year Additions Deletions
2010 13% 12%
2013 15% 15%
2015 15% 15%
2016 15% 13%
2017 13% 13%
2018 11% 12%
2019 13% 10%
2020 10% 10%
2021 11% 11%

As Table 13 sets out, we also expect to see a higher proportion of changes being picked up during the canvass period, compared to the rest of the year, in years without UK-wide elections (e.g. 2018) – a trend that continues in 2020 and 2021.

Table 13. Percentage of additions during and outside of canvass period 2015-21



During canvass


Outside canvass


During Canvass


Outside canvass

2015 40% 60% 58% 43%
2016 38% 64% 54% 47%
2017 39% 61% 56% 44%
2018 68% 32% 68% 32%
2019 62% 38% 61% 39%
2020 56% 44% 64% 36%
2021 61% 39% 61% 39%

This point is also supported by the 2021 data on the proportion of additions and deletions recorded during the canvass period across the three nations of Great Britain (see Table 14). The proportion of additions and deletions during the canvass were lowest in Scotland (39.0% and 55.0%, respectively), followed by Wales and then by England. This is in line with the level of engagement at the May 2021 elections where turnout was highest in Scotland, then in Wales and lowest across England.

Table 14. Additions and deletions during full year and canvass period per nation



Full year


Canvass period


% during canvass 


Full year


Canvass period


% during canvass

England 4,308,807 2,777,863 64.5% 4,674,707 2,875,974 61.5%
Scotland 455,341 177,552 39.0% 415,722 228,843 55.0%
Wales 245,670 112,310 45.7%     232,649 137,629 59.2%
Great Britain 5,009,818 3,067,725 61.2% 5,323,078 3,242,446 60.9%

It is important that the canvass and other year-round registration activity continues to provide a high quality register at all times in order to avoid significant updates needing to be made in advance of major polls. We have previously highlighted our concern that the registration system, including the canvass, is unlikely to be sustainable in the longer term and have recommended that governments should explore more automated registration processes. For example, regular access to reliable data from a wider range of public services about people who have recently updated their address details would allow EROs to make contact directly with them at their new address to encourage them to register to vote. Integrating electoral registration applications into other public service transactions could also make it easier for individuals to keep their registration details up to date and accurate.

While canvass reform has addressed one aspect of sustainability – the resource and capacity taken up through unnecessarily chasing households where there has been no change – it is not yet clear what its impact is on the other key aspect – the system’s ability to pick up population changes away from major electoral events. Our next accuracy and completeness study will allow us to more clearly assess the overall impact on the registers, as it will take place after three years of the reformed canvass in Great Britain.


Download the electoral registration data 2021

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First published: 16 May 2022

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