The prime minister should have had a ‘Dover speech’ moment, reflects Will Straw to Richard Angell and Adam Harrison

With the consequences of Britain’s shock Brexit vote still unfolding, any reluctance from the bruised leadership of the Britain Stronger In campaign to confront the causes of last month’s devastating defeat would be understandable. But as we meet at the organisation’s headquarters, executive director Will Straw wastes no time in asserting his view of where it all went wrong: ‘In the end it became a referendum on immigration rather than the question of Britain remaining in the EU, and we had no coherent response to that’.

‘We tried to take on the negatives head-on by talking about the number of immigrants working in the NHS and about the economic benefits that EU migrants have brought to the economy overall.’

Ultimately, this message failed to cut through, something Straw attributes to the political backdrop to the campaign: ‘Whenever a Conservative went up, they were hamstrung by their ludicrous migration cap’. Labour, meanwhile, had an entirely incoherent message, he argues: ‘The grandees had to defend the 2004-5 accession, while the Corbynites said, “There’s no problem at all – happy days”.’

This left the campaign struggling to wrest the arguments back to the economic risks of Brexit until the final week of the campaign: ‘By then it was probably too late’. Could anything have been done to drastically alter the narrative leading up to the vote? Straw and others within the campaign argued for a major intervention by David Cameron: ‘Not with a week to go, but with a month to go, or six weeks to go, the prime minster should have had a Dover speech moment, similar to what Tony Blair did in 2005, and taken head-on the immigration argument.’

The prime minister could do nothing but fall on his sword after his catalogue of errors: ‘He started his leadership of the Conservative party by pulling them out of the mainstream European People’s party. He, as prime minister, walked out of [European] council meetings’. It was therefore always set to be an uphill struggle: ‘[Cameron then had to] turn on a sixpence to say that it would be catastrophic if we left the EU. I think that really hurt the credibility of the campaign. Similarly, again although significant, the focus on the renegotiation from December to February meant that the news agenda was focused on immigration and sovereignty rather than economic benefits, cooperation, Britain’s place in the world. I think that did us damage at quite a crucial stage in the campaign.’

While damning of Cameron’s strategic approach to the referendum, how did Straw find it to work with Conservatives? ‘They are very professional. They are very driven by the evidence. They are very keen to understand what makes up your support and how you can maximise it, and so there’s very little that’s done on sort of whimsy or received wisdom.’

He commends Labour In, specifically for the ground operation it put in place on a regional basis. But since the result, Straw has made no secret of his view that its efforts were impeded by the Labour leadership: ‘[Labour In] had one hand tied behind their back because of a complete lack of interest from Jeremy Corbyn and his closest aides’.

‘There was one occasion where we cleared a day for John McDonnell, who put a statement out mid-afternoon the day before criticising the campaign. This was space we created for him, criticising the campaign, and then later in the day, we learned that he had pulled out of going on the Today Programme the next morning, meaning there was a complete gap … From that point, we resolved that it was critical to get Labour voices in the news, but we would have to do a lot of that ourselves.’

While the Leave camp’s NHS pledge has already unravelled, Straw is sceptical of whether it will ever live up to its allusion that leaving the EU will lead to lower immigration: ‘I thought the most interesting moment of the BBC debate two days before the referendum was when Frances O’Grady called out [Leave] for not actually wanting to cut migration. They had been producing literature particularly for south Asian communities saying that migration would rise from Commonwealth countries if only we left the EU. It was a con trick.’

With Straw certain that immigration was the issue that ultimately determined the referendum’s outcome, he considers it the ultimate irony and a betrayal of voters when those who propagated this argument are exposed as liars: ‘There will be a lot of anger from people if immigration isn’t reduced, even if many of us don’t think that’s the right approach. Ultimately, it may be for Boris Johnson and Michael Gove to explain why they gave that impression but couldn’t deliver it.’