Peterborough and Postal Voting

The Peterborough by-election was the first such election induced by the Recall of MPs Act 2015, after a successful recall petition removed Fiona Onasanya — following her conviction for perverting the course of justice.

Lisa Forbes, the Labour candidate, narrowly held the seat from the Brexit Party.

In response, numerous assertions about postal voting and vote choice have been made — to imply electoral fraud. This article looks at these claims.

The Result

The by-election turnout was 48.4% — over two-thirds of the 2017 turnout (67.5%). The turnout among postal votes was 69.4%. The Peterborough City Council results website does not currently contain the count of postal votes.

Countering Conspiracies

A Twitter account called ‘The Core’ posted, in block capitals (and shared over 1,700 times):



Checking the House of Commons Library’s briefing paper on election statistics, around 20% has been the standard share of valid votes cast by post in the last two general elections.

You could also use total ballots at the count as a base for the percentage, which would be slightly lower.

For Peterborough, the 2017 figure was 24%. If 6,000 votes were cast by post, then the 2019 by-election postal vote share is lower than in 2017. The BBC states that 9,898 votes were cast by post (29%).

Peterborough is not an usual constituency for postal voting. (Map: Owen Boswarva)

It is not unusual for one in five valid votes to be cast by post — it is typical.

‘Brexit Party are leading in the polls. This doesn’t add up’

The same account also suggested — because one poll read a six point lead for the Brexit Party — this somehow invalidates the by-election result.

Votes are plainly not uniform across the country. This is why different parties win different seats.

Vote shares vary geographically. (Image: BBC)

This is a crude calculation. However, if we take the average of four published polls since the European Parliament elections in late May, and project the national difference in voting intention onto the estimated European result for Peterborough, we basically recover the by-election result.

The Peterborough result was entirely consistent with national polling.

Some people confuse the latter YouGov poll of Great Britain for a survey of Peterborough.

There was no polling for the Peterborough by-election.

‘Postal vote turnout was incredibly high’

David Craig of Snouts in the Trough asserts the following as “fact”:

Fact 2 — Turnout amongst postal voters was 69.4%. That is an incredibly high turnout

James Holland, who writes for CapX, describe the postal vote turnout as “massive”.

A postal vote turnout of 69.4% would be relatively low. In all except four general elections since 1945, over 80% of postal ballots issued are counted at the ballot box. It is reflective of the lower turnout we see at by-elections.

‘The by-election result was different to the European election’

A public account on Facebook suggests that it is “very suspect” that the European elections and Westminster by-election results differ in their result.

There are three errors here. Firstly, the ‘EU result’ for Peterborough is actually for Peterborough City Council. This is a wider area than the Peterborough constituency for Westminster. The city includes wards which are part of the North West Cambridgeshire constituency.

This is plain when you look at a map of the boundaries. (Image: Ordnance Survey)

Secondly, psephologists typically look at vote shares and changes, to account for different turnouts in elections.

Thirdly, people vote differently in different elections. This is supported by decades of social research. It is not remotely surprising or suspicious.

As an example, Rallings and Thrasher looked at the differences in concurrent local election and European Parliament election votes across Britain in 2004:

The pattern of party choice at the two types of contest also varied considerably. The three major political parties together took a much larger share of the overall vote at the local than at the European elections, and each independently ‘lost’ a sizeable number of its local votes to smaller parties.

Not all elections are the same.

And finally

This blog looks at the use of statistics in Britain and beyond. It is written by RSS Statistical Ambassador and Chartered Statistician @anthonybmasters.

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