Speaking at events before the referendum last year, I took to asking the audience who they thought would win. Throughout, the BritainThinks poll of polls stubbornly showed remain and leave neck and neck, and in the “short campaign” more polls favoured leave than remain. But a show of hands drawn from the usual audience of business leaders, journalists and politicians consistently and confidently predicted a remain victory.

One eminent commentator, often speaking on the same platforms as me, promised: “Remain will win, and will win big”. Another observed that the “great British public would look over the brink, and then vote for the status quo … as they always do”. Discussion usually focused on the inevitability of voters “seeing sense”.

We all know what happened next. But after 23 June the movers and shakers, who had been so sure they were right during the campaign, were, well, still pretty sure that they were right. I was asked again and again to share how my polling and focus group insight revealed voters’ deep disappointment: how leavers, who were now obviously regretting their folly, would vote differently given the chance. The evidence did not support this at all.

Put simply, those who voted leave felt positive, even passionate, about the result – one focus group member told me: “When I woke up and heard we’d gone Brexit, I felt like England had won the World Cup”, going on to describe leaping out of bed and running around punching the air with joy.

Although a small number of remainers did indeed feel the grief that some commentators observed, overall their views were more ambivalent. By November, a similar number of those who voted remain (20%) said they had “come to terms with the result”, as said they felt “depressed” about it (22%); just 5% agreed that “Brexit can still be averted if the remain side continue to put their case to the public”.

Asked to score on a scale of 0 to 10, with 0 being certain that Brexit will be bad for Britain and 10 certain that it would be good, the same poll also found that leavers were significantly more likely to be positive than remainers were to be negative: 41% of leavers scored 10, while just 27% of remainers scored 0.

BritainThinks’ focus groups highlighted concerns about the slow pace of change, and suspicion that the government was deliberately dragging its heels to avoid carrying out the will of the people – a suspicion that was often felt as strongly by people who voted remain as by those who voted leave.

It was against this backdrop of mounting dissatisfaction with the government’s performance that Theresa May set out her stall yesterday, with 57% – up 4% since December – now saying the government is doing badly.

Although a small majority still think that, in hindsight, Britain was right to vote to leave, there are specific issues to address and growing concerns that we will be worse off economically, with less influence in the world after leaving the European Union, and that leaving will have a negative effect on jobs and pensions.

To really understand how, if at all, these attitudes change as negotiations get under way, BritainThinks has set up an innovative project, working in partnership with the Guardian.

The Brexit Diaries will track the views of 100 ordinary British men and women: 48 who voted remain and 52 who voted leave. Each week they will record what they have noticed, worried about and rejoiced in as Britain prepares to leave the European Union, providing a unique insight into the national mood beyond the Westminster bubble.

The first diary entries, drafted ahead of the prime minister’s speech, make sober reading. Trump, the NHS and extreme weather conditions have all made a far greater impact than anything to do with Brexit. The commentariat will pore over the speech, but voters are more likely to judge the government on what it does rather than what it says.