James Frayne is Director of communications agency Public First and author of Meet the People, a guide to moving public opinion. 

Justine Greening has come out in favour of a second referendum. What would it mean for the Conservative Party if it went down this route? We can never know for sure, but we can make reasonably confident assumptions by looking at the polling that focuses on the second referendum option specifically, and looking at continued public attitudes towards the EU.

Firstly, let’s look at the existing polling. The most recent poll on this issue was by YouGov, with the fieldwork taking place on 10-11 July. Asked whether there should be a referendum “once the Brexit negotiations are complete and the terms of Britain’s exit from the EU have been agreed”, people overall rejected the idea by 41-37 per cent, with the rest saying “don’t know”. This might not appear to be a terrible policy by the standards of political polling, but it largely mirrors the state of the electorate in the referendum – split down the middle, leaning towards Leave.

However, we need to look at some of the cross breaks within the poll to understand the impact on the Conservative Party. In this poll, Conservative voters rejected a second referendum by 71-15 per cent and Leave voters by 63-18 per cent. This is significant because it demonstrates the strength of feeling that exists amongst those that voted Leave and that now vote Conservative.

A YouGov poll of Conservative Party members, between 5-8 July revealed a similar picture. By 82-14 per cent, members rejected a second referendum, and Leave-voting Conservative members rejected a referendum by 92-4 per cent. Asked how the Government should proceed with Brexit, giving people a range of options, the overwhelming majority (77 per cent) said we should continue with Brexit on current negotiating terms; nine per cent said we should seek a softer Brexit; and just seven per cent said we should offer a second referendum; three per cent said we should abandon Brexit.

There appears somewhat more support for a referendum amongst left-leaning voters and activists.

A poll by YouGov of Unite members showed they believe there should be a referendum on the terms negotiated for our exit, by 57-34 per cent. And by 49-39 per cent, Unite members believe the union should campaign for a referendum on these terms. (Not all Unite members vote Labour, of course.)

On the other hand, a poll of Labour members in March asked whether it was right that Owen Smith was asked to stand down by Jeremy Corbyn for demanding a second referendum, and people said it was right by 50-37 per cent. (Of course, we must treat this poll with caution; there are many, many other influences in play with this question – most obviously, how the two politicians are seen – but it’s interesting nonetheless.)

But what do the polls say about attitudes towards the EU more generally? The most important question here is the one that asks people whether it was “right or wrong” in hindsight to leave the EU. Here, the polls have been essentially static for months, with people leaning towards “wrong”. The most recent poll has people saying wrong by 46-41 per cent, and it has been in this position for many months (although people have moved towards wrong from right since 2017, when polls often pointed to right). Different people will read these polls in different ways. Some might say that the effective narrow lead for Remain means people are starting to see the light. I think this is wrong. As I’ve written in the past, I think it’s extraordinary that opinion has stayed so eurosceptic despite all the negative coverage in the media, and I think this suggests the Leave vote is incredibly hard.

What does all this mean? It’s hard to judge that offering a second referendum would be anything but a total disaster for the Conservative Party. It would not only be a direct breach of trust with most of the electorate – including many, but obviously not all, of those that voted Remain. It would also strongly indicate that the Party wanted to stay in the EU, which would further irritate grassroots. The Party is already seeing what happens when you appear to go back on promises made on the EU; Greening’s policy would amplify those problems vastly.