If Britain were a car it would be a Bentley, says Lorraine Beerman. Grand, impressive, prestigious. A split rumbles within the room – a focus group of older Leave voters from greater London. Perhaps a Jaguar might better represent the country, suggests someone. A debate is had on what car Britain would like to be and what car it actually is. At the moment, sighs another attendee, Britain is a dinky Ford Fiesta. Beerman bristles.

A manicurist from Potters Bar who lives with her husband of 22 years, Beerman is one of the 58% of Leave voters who feels optimistic about the future. She is a homeowner with an active social life, her adult children are settled and, despite a pervasive sense of Brexit fatigue, she is content.

“We have security since we downsized, I have a stable marriage, which is important, and as it stands at the moment I feel very confident Brexit will go ahead in October,” she says brightly. All of her friends are “on the same page”, given that politics now “always comes up” at dinners and gatherings with friends. “We don’t want an extension, and if we leave with no deal, so be it, that would be fine. We can work through things once we’ve come out.”

But findings from the thinktank BritainThinks, polling more than 2,000 adults across the UK, reveal a starkly despondent national mood; 69% of adults feel pessimistic about national unity and 72% believe that, within a year, Britain will become more divided than it already is. Only 20% of Remain voters feel very or fairly hopeful about the UK’s future. Dean Stevens, a 49-year-old warehouse supervisor from Leicester, lays the blame squarely at the feet of politicians.

“We were a United Kingdom, but we’re a divided kingdom now. There doesn’t seem to be a way out of the doom and gloom that isn’t terrible. You see playground antics from the people you’ve elected – they’ve fuelled a fire in people, made it tribal and everyone’s out for themselves. There’s more deceit in politics now than there has ever been.”

Stevens lives with his fiancee and their two 15-year-old boys, and is Leicester born and raised. In December the confectionery factory he works in will close and move to York. “I have no job security. Economically, things are worse. I’m pretty much earning the same wage I was earning 10 years ago: there haven’t been any raises.” The rising cost of living worries him. His son asking for “£160 trainers” appals him. Stevens mourns the lack of community and closure of pubs in his local area, but won’t go into town because he feels it has become too violent; two of his friends have been mugged there in the past couple of months.

According to the survey, anxiety about crime has rocketed up the agenda. One in five adults say it’s likely they or someone they are close to will be a victim of crime in the next year or so; this rises to 29% of those living in London. Homelessness and poverty also rank high; almost 70% of the public feel worried about both.

Like almost three-quarters of the UK, and 82% of those aged 65 and over, Stevens and Beerman feel an acute sense of national decline and an erosion of British values – defined as “respect, manners, pride”. Beerman is bitter about the role she feels immigration has had to play in this. “Without sounding prejudiced, we have so many immigrants taking advantage of the NHS, so many come here not to work and live off benefits.” That the NHS might have ceased to exist without its immigrant workforce is not an argument that persuades her.

The subject remains sore within the focus groups. In London, Simon Liu, 40, believes a lack of integration from immigrants has led to a loss of community. “[They] need to integrate, otherwise there will be more problems”. His parents are Chinese immigrants from Hong Kong and he describes himself “as obviously not ethnically British”, but still proudly feels “ingrained” in British society: “I am British absolutely, it’s part of me.”

The split between those who identify as “haves” and “have-nots” stands at 52% to 48%, with the young and those from lower socioeconomic grades far more likely to count themselves in the latter. Voters are no longer simply cynical and apathetic, but are actively engaged in politics – 40% say more so since Brexit, rising to 50% of 18-to-24-year-olds. Yet the majority of Britons have lost faith in the entire political system: three-quarters of the public believe that Britain’s political system is not fit for purpose and that the country is an international laughing stock. Only a fifth believe the next prime minister will be up to the job.

Carlo Robbie, 32, who lives and works in east London, says “the expenses scandal didn’t change the way I viewed politicians necessarily”, but that the current political crisis has had him in utter despair. “I got very emotionally involved and had to take steps to find a way to detach from it.”

He is now retraining to become a psychotherapist and does regular volunteer work. Like 72% of those polled, he does not believe that politicians understand the British public. “Any solution has to come from the middle: it can’t come from the far right or the far left because it won’t unify the country. Somehow the majority in the middle needs to be heard above all the name-calling rhetoric about Remoaners and Leavers.”