Assisted Dying: how MPs voted and what it tells us about ‘cross-party consensus’

Whenever there is a high-profile free vote – like that over assisted dying – you will see claims that it cuts across party lines: that the issues involved are “non-party”, “cross-party”, or “not issues of party politics”. This is all partly true, although it also reflects an anti-party sentiment that has long existed.

At the beginning of the 20th century, writer Sidney Low noted that the easiest way to get a round of applause at a public meeting was to claim that something was non-partisan. “No sentiment”, he said, “is likely to elicit more applause at a public meeting, than the sentiment that: ‘This, Mr Chairman, is not a party question, and I do not propose to treat it from a party standpoint’”. Not much has changed since, except that we now have fewer public meetings.

That these issues split the parties is obvious. This is in large part why they are free votes. It is a lot easier to allow MPs to vote as they like rather than trying to impose a whip. Free votes are often more an acceptance of reality rather than some grand constitutional principle.

When they come before parliament, issues put to a free vote tend to be supported and opposed by a range of MPs on all sides. Advocates therefore often stress the cross-party nature of their support. This is unusual given that most normal votes see complete party cohesion, with no MPs voting against their party line. As a result, the issues are usually reported differently in the media. Precisely because they are not the norm, the free vote and the extent of cross-party support are highlighted, as the focus of reporting is not (as it usually is) the split between government and opposition.

The media and politicians tend to concentrate on the exceptions (MPs voting against the majority of their party) and overlook the norm (most MPs not doing so). Perhaps the worst example of this I have seen was when two Labour MPs voted against banning fox hunting in 1997 and eight Conservative MPs voted in favour of a ban. This was reported by The Times as saying they had “defied conventional wisdom about the politics of hunting”. Yet 374 Labour MPs (99% of those voting) supported a ban, 128 Conservatives (94%) opposed it.

Reform and Labour split

There are two rules with so-called conscience votes. The first is that usually, even with the whips off, the majority of Labour MPs will go in one lobby and will face the majority of Conservative MPs in the other. The second is that, while these issues split some of the parties some of the time, they rarely split all the parties all of the time.

The vote on Labour MP Kim Leadbeater’s bill on assisted dying is a good example. All the larger parties split, as did some of the smaller parties. But the divisions were not equal.

To measure the extent of the divisions we can use a measure called the index of party unity. It’s pretty basic: you subtract the minority percentage of a party’s voting MPs away from the majority and divide by 100. A united party scores 1.00. One that has split right down the middle scores 0.00.

At second reading in November, Reform and Labour split the worst over the assisted dying bill. Both had roughly 60/40 splits, producing scores of 0.20 and 0.23 respectively. (I have included tellers in all calculations). These are relatively deep splits, if not record breakers. There have been multiple occasions on which parties have divided worse than this in the past. Without breaking sweat, I can show you deeper splits than 0.20 among the major parties on a range of issues from capital punishment to divorce, from the compulsory wearing of seatbelts to the age of consent, and from obscene publications to embryo and stem cell research.

The majority of the Liberal Democrats (0.69), Plaid Cymru (0.50), and all the Greens (1.0) also voted in favour of assisted dying, as did one independent MP and one SDLP MP.

The majority of Conservative MPs voted against (an 80/20 split, so a score of 0.60), along with most of the independents who voted, and the majority of the MPs from Northern Ireland (the DUP’s 1.0 score mirroring the Greens). And the SNP abstained en bloc.

So of the parties with more than two MPs who voted, the issue split two parties quite badly, caused some division among three, and saw unity among two.

For all we talk about them being non-party, and even with the whips off, the outcome of free votes is largely dependent on the partisan composition of the House. Holding everything else constant, had there been 100 fewer Labour MPs and 100 more Conservatives taking part, the Leadbeater bill would have fallen at second reading by a majority of one.

This article first appeared in 'The Conversation' on 2 December 2024