More Brexit election numbers

The Brexit circus continues in Britain, with the supreme court in London now having heard two days of argument on the legality of prime minister Boris Johnson’s advice to the queen to prorogue parliament. Most observers think that the court will overturn last week’s decision by the Scottish court of session that the prorogation was void.

The House of Commons may or may not have been validly prorogued, but it remains true that its dissolution cannot be long averted. Although its term does not expire until May 2022, its chance of surviving that long is almost nil. One way or another there will be an election quite soon, probably in either late November or early December.

Last month we had a look at some possible outcomes for an election, obtained by projecting results from the election to the European parliament held in May. That election represented the nadir of the fortunes of the two major parties – the governing Conservatives, who placed fifth, and the opposition Labour Party, which managed third.

But a general election will be a different beast. The protest vote element from the European election will be absent – after the last few weeks, no-one can doubt that the House of Commons is genuinely powerful – and the pull of tradition will return many voters to the major parties. The question is, how many?

Johnson’s success hinges on his hopes of stealing the thunder from Nigel Farage’s Brexit Party and consolidating the Brexit vote under his own banner. Similarly, the chances of success for Labour’s Jeremy Corbyn will be improved to the extent that he can unite the opponents of Brexit behind him.

If both these things happen, they will tend to cancel out. And so far, that’s what the opinion polls are showing. The Conservatives have won back most of Farage’s vote, and support for the Liberal Democrats and Greens, while well above 2017 levels, has leaked back to Labour since the mid-year peak.

To see what this means in terms of seats, I plugged in some numbers from the average of this month’s polls. Assuming uniform swings, I simply adjusted the parties’ performance in each seat according to its movement since 2017 across the whole of Great Britain (or of Scotland, in the case of the Scottish Nationalists).

That gave me the following: Conservatives down three to 314, Labour down 35 to 227, Lib Dems up 20 to 32, Scottish and Welsh Nationalists up 17 to 56, and the Brexit Party winning a single seat. (Ell Smith tried a similar exercise last week and got very similar numbers.)

In substance that’s much the same as the existing house. It would still be very evenly divided; exactly how it would behave would depend on just what becomes of the Conservative Party. Would some of its already-declared rebels hold their seats as independents, and how many future rebels might be returned among its ranks?

Either way, poor prospects for a clear resolution of the Brexit question. There is an upside for the opposition, though. While it is hurt by the fact that its vote is currently more divided, it means it has potentially more to gain from tactical voting.

To test this, I re-ran the numbers, adding the assumption that on each side, half the supporters of the parties that were trailing in each seat would switch their vote to whichever party was best placed to win it for their side (pro- or anti-Brexit, as the case may be).

That makes quite a difference. On the original figures, Labour stood to lose 23 seats to the Conservatives. With tactical voting, it would lose only ten and pick up two, for a net movement of eight.

Totals would be: Conservatives 300, Labour 242, Nationalists 56, Lib Dems 31, Brexit and Greens one each. Northern Ireland then adds about another eight seats net to the pro-Brexit side – not because the Conservatives’ ally there, the DUP, do so well, but because their Sinn Féin opponents don’t take their seats.

Even so, that would be a small but workable majority for a coalition of Labour, Lib Dems and nationalists. It would be brittle, but it would offer a path forward to a new referendum on Brexit, which seems the only way the issue can possibly be sorted out.

We know that swings are never uniform, and it’s fair to assume that there will be some shifts in support before an election is finally held. So the final picture could look very different. Once again, however, Britain’s creaky nineteenth-century electoral system stands between popular opinion and realisable outcomes.