From David Cowling – former head BBC political research

Because the 2020 local elections were postponed due to the pandemic, this May will witness elections for incumbent candidates who were, overwhelmingly, last elected in either 2016 or 2017. Both national opinion polls and projections of national vote shares at the time suggest two very different benchmarks against which to measure the 2021 results.

Those elections taking place with a 2016 benchmark are: the Scottish Parliament, Welsh Senned, London Mayor, Greater London Assembly, the city mayors of Bristol, Liverpool and Salford, Police & Crime Commissioners, and councillors in over one hundred English local authorities.

Those with a 2017 benchmark are: 6 Metro Mayors – Cambridgeshire & Peterborough, Greater Manchester, Liverpool City Region, Tees Valley, West Midlands and West of England, two city mayors in Doncaster and North Tyneside, and councillors in 21 English Shire Counties, one Metropolitan District (Doncaster) and six Unitary Authorities (Cornwall, County Durham, Isle of Wight, Northumberland, Shropshire and Wiltshire).

Westminster voting intention polls are not predictors of outcomes in local or devolved elections: the latter are different political institutions with different functions and powers and voter turnout for them is usually significantly lower than in Westminster elections. However, they do offer a broad indication of the relative popularity of political parties at various times.

In the run-up to the 5 May 2016 local elections, Westminster voting intention polls suggested fairly even levels of support for Conservative and Labour, with the Lib Dems pushed into fourth place by UKIP. The table below gives the average poll figures for March and April 2016 (the full list of polls can be found as an appendix below).

Monthly average	Con	Lab	LD	UKIP	Green	Oths.
	%	%	%	%	%	%
April 2016	35	32	7	16	4	7
March 2016	36	33	7	14	4	6

The polls published in the run-up to the 4 May 2017 local elections suggested a very different story: the Conservatives were 20 points ahead of Labour, the Lib Dems were narrowly back in third place and UKIP’s support had halved compared with 2016. The table below gives the average poll figures for April 2017 (the full list of polls can be found as an appendix below)

Monthly average	Con	Lab	LD	UKIP	Green	Oths.
	%	%	%	%	%	%
April 2017	47	27	10	7	3	6

As United Kingdom governments have never invested in a national system for the immediate collection and tabulation of local authority votes, two estimates have emerged that regularly feature in discussion following the close of voting on polling day. Based on extensive samples of results collected in the immediate aftermath of each election, both aim to represent what the party vote share would have been if the whole country had participated rather than just the councils with elections each year.

One estimate is the BBC’s Projected National Share (PNS) which is usually broadcast during the broadcaster’s overnight election results programme. The other is the National Equivalent Vote Share (NEV) compiled by Colin Rallings and Michael Thrasher and usually published in the first Sunday Times edition following polling day.

I have set out the run of both estimates from 2010-19. They mirror the significant difference in party support between the 2016 and 2017 local elections as evidenced in the Westminster voting intention polls: both show a one point difference between Conservative and Labour in 2016, compared with an eleven point difference in 2017.

Projected National Share (PNS) of the vote (BBC) 2010-19

	Con	Lab	L. Dem	UKIP
	%	%	%	%
2010	35	27	26
2011	35	36	16
2012	31	38	16
2013	25	29	14	23
2014	29	31	13	17
2015	35	29	11	13
2016	30	31	15	12
2017	38	27	18	5
2018	35	35	16	Others
2019	28	28	19	25

National Equivalent Vote (NEV) Share (Rallings & Thrasher) 2010-19

	Con	Lab	L. Dem	Others	UKIP
	%	%	%	%	%
2010	37	30	24	10
2011	38	37	16	9
2012	33	39	15	13
2013	26	29	13	10	22
2014	30	31	11	10	18
2015	36	32	10	10	12
2016	32	33	14	9	12
2017	39	28	18	11	4
2018	37	36	14	13
2019	31	31	17	17	4

The other obvious measure of relative performance is the total of seat gains and losses by the various parties in each set of elections. Once again, there is no official collection of these results that allows a national picture to be created. Over many years the Press Association (PA) has published their own totals of council seats gained and lost by the parties, and Colin Rallings and Michael Thrasher publish their own totals. It is rare that such totals result in the same figures: the PA measures gains and losses from the status of each seat at dissolution rather than when it was contested four years earlier (if someone was elected as UKIP but subsequently joined the Conservative group on her council, then the PA would  designate the seat being defended as Conservative); Colin and Michael would not as they calculate a seat by the party that won it at the appropriate previous election (also, Colin and Michael produce notional results for re-warded seats which the PA does not). I have used the PA figures for local election results 2010-19 for the purposes of this note. Clearly, one significant factor in outcome is often the total number of seats up for election. We can see from the table below that there were almost twice as many seats contested in 2017 than in 2016.

Net gains and losses at council elections 2010-19

Year	Con	Lab	Lib Dem	Others	Total seats
2010	-93	+391	-208	-50	4,223
2011	+85	+857	-747	-208	9,460
2012	-328	+534	-190	-52	2,412
2013	-337	+290	-125	+172	2,439
2014	-236	+324	-310	+233	4,262
2015	+539	-201	-419	+55	9,352
2016	-48	-18	+45	+21	2,782
2017	+563	-382	-42	-139	5,211
2018	-33	+77	+75	-119	4,404
2019	-1,269	-63	+676	+434	8,410

However, the difference in total numbers of seats does not explain the different outcomes in the two elections. The neck-and-neck race between Labour and the Conservatives in Westminster polls prior to the 2016 local elections appears to be reflected in the small net gains/losses recorded at that election. By contrast, the significant Conservative lead over Labour in polls in the run-up to the 2017 election appears to play at least some part in explaining the substantial Conservative gains as well as Labour losses which occurred then. Government parties are usually vulnerable in local elections. 

The past would suggest that, in 2021, the Conservatives are particularly vulnerable in the seats they are defending from 2017.

Whilst the benchmarks for this set of elections are either four or five years ago, we should not forget the remarkable features of the most recent set of local elections in 2019. The Conservatives sustained their biggest local election losses since the mid-1990s and Labour’s contribution to this massacre was to register a net loss of seats as well. The beneficiaries were the Lib Dems who, according to Colin Rallings and Michael Thrasher, made “their biggest single jump in councillor numbers since 1987”; and Independent/Other candidates who took 14.1% of all the seats – their highest total in at least 20 years, having only reached double figures on three previous occasions during that period. 

In the introduction to their 2019 Local Election Handbook, Colin Rawlings   and Michael Thrasher observed:

“ Local voters are demonstrating frustration with the behaviour of the two main parties. Together the parties haemorrhaged more than 20 percentage points from the 85% of the vote they took in combination in 2017 as English local government once again took on a more fluid and multiparty look”. It will be a matter of keen interest for many as to whether the voter frustration, so manifest in May 2019, persists in May 2021.

Westminster voting intention polls in the run up to the 5 May, 2016 local elections

			Con	Lab	LD	UKIP	Green	Oths.
April 2016			%	%	%	%	%	%
Opinium*	26-29.4	2,005	38	30	5	15	4	8
YouGov*	25-26.4	1,650	30	33	6	20	3	8
BMG*	22-26.4	1,315	33	32	6	18	5	6
MORI	16-18.4	1,026	38	35	6	11	3	7
ICM	15-17.4	1,003	38	33	7	13	3	6
ComRes*	13-14.4	2,036	35	30	8	16	4	6
YouGov*	11-12.4	1,693	31	34	8	17	3	7
March 2016
Opinium*	29.3-1.4	1,966	33	32	5	17	4	9
BMG*	24-29.3	1,298	36	31	7	16	5	6
MORI	19-22.3	1,023	36	34	10	11	3	6
ComRes	18-20.3	1,002	37	35	7	9	4	7
YouGov*	16-17.3	1,691	33	34	6	16	3	7
ICM	11-13.3	1,001	36	36	8	11	3	5
ComRes*	9-10.3	2,059	38	29	7	16	4	5

Westminster voting intention polls in the run up to the 4 May, 2017 local elections

Pollster	Fieldwork	Sample	Con	Lab	LD	UKIP	Green	Oths.
2017			%	%	%	%	%	%
Opinium*	2-3.5	2,005	46	30	9	7	2	5
YouGov*	2-3.5	2,066	48	29	10	5	2	6
Panelbase*	28.4-2.5	1,034	47	30	10	5	2	6
Kantar*	27.4-2.5	1,205	48	24	11	7	4	6
ICM*	28.4-2.5	1,970	47	28	8	8	4	4
YouGov*	27-28.4	1,612	44	31	11	6	2	6
ICM*	26-28.4	2,012	47	28	9	8	4	4
Opinium*	25-28.4	2,007	47	30	8	7	3	6
ORB*	26-27.4	2,093	42	31	10	8	n/a	9
YouGov*	25-26.4	1,590	45	29	10	7	3	6
MORI	21-25.4	1,004	49	26	13	4	1	7
ICM*	21-24.4	2,024	48	27	10	7	3	5
ComRes	20-24.4	1,001	48	29	11	3	2	7
Kantar*	20-24.4	1,196	46	24	11	8	4	7
Panelbase*	20-24.4	1,026	49	27	10	5	3	6
Survation*	21-22.4	2,072	40	29	11	11	2	7
YouGov*	20-21.4	1,590	48	25	12	5	3	6
ICM*	19-21.4	2,027	48	26	10	8	3	5
ComRes*	19-20.4	2,074	50	25	11	7	3	4
ORB*	19-20.4	1,860	44	29	8	10	n/a	10
Opinium*	19-20.4	3,003	45	26	11	9	3	4
YouGov*	18-19.4	1,727	48	24	12	7	2	7
ICM*	18.4	1,000	46	25	11	8	4	6

David Cowling