Old Bexley and Sidcup By-Election

This page first posted 6 December 2021

The Conservatives held the Old Bexley and Sidcup seat with a clear majority and that's not a big surprise. The voters there are generally right-of-centre economically, socially conservative and nationalist, with 60pc voting to leave the EU. The seat is the 121st safest Conservative seat in the country and, if Labour could win it in a general election, they would also get a landslide Commons majority of 230 seats.

But let's look behind the obvious to see what this really tells us about voters' opinions. To help, Electoral Calculus and pollster Find Out Now conducted an MRP poll for the Telegraph this week. MRP (or regression) polls are a relatively newfangled way to crunch the numbers which helps to reduce polling error and also gives estimates of how each and every seat would vote if there were a general election (rather than a by-election) tomorrow.

Our poll of over 10,000 people was taken from Monday to Wednesday this week just ahead of the by-election. Overall it shows a Conservative lead over Labour of just 1pc, which is a lot less than their lead of 12pc at the last general election. In terms of seats, the poll predicts the Conservatives would win 288 seats, with Labour on 271. Although the Conservatives are the largest party, it would be hard for them to form a government and it is more likely that Keir Starmer would enter number ten as Prime Minister, possibly with SNP acquiescence. As Chris Holbrook, CEO of Find Out Now, said "a tough month for the Conservatives is making some previously solid Tory seats look shaky".

Since our poll has the MRP feature, it can also predict the likely general election result in Old Bexley and Sidcup. That prediction is 53pc for the Conservatives (compared with 51pc at the by-election) and 27pc for Labour (compared with 31pc at the by-election). Comparing the actual by-election result with the prediction seems to show that things are a little bit worse for the Conservatives than our poll.

But by-elections are strange electoral events, with potential for protest votes and tactical voting aplenty. The Chesham and Amersham by-election in June this year saw the Liberal Democrats confound expectations by overturning a chunky Conservative majority. In Old Bexley, the Reform UK party (formerly the Brexit party) did quite well by coming third with 7pc of the vote. And the Liberal Democrats and Greens did relatively badly as they were squeezed by Labour.

Predicted seats won with and without Reform UK

Looking at things in a left/right way, the two right-of-centre parties together got 58pc of the vote, and the three left-of-centre parties had 38pc. Compared with our MRP predictions of 56pc and 43pc respectively, that is actually a better than predicted result for the right and a worse for the left.

This fits a pattern in recent by-elections where voters have not shown much positive enthusiasm for Labour. Labour suffered a bad loss in Hartlepool, made little progress in Airdrie and Shotts, and had a sharply reduced majority in Batley and Spen. Labour needs to unify left-of-centre voters and get some oomph behind itself.

For the Conservatives, their corresponding tasks are to keep the right-of-centre voters as unified as they were at the last election and to try to bounce back from this mid-term slump. If they can win back those Reform UK voters, or pull back some support from the centre, then they have a chance of a modest majority at the next election. But if things stay as they are, then this result is not such great news for the Conservatives as it might look.