Look at the people here in Manchester at the Tory party conference, stare into their eyes and they look much as they always did – ordinary home counties folk, small business people, plus a few sharp-suited would-be spads. Not noticeably odd, yet these party members are the tiny group who have done for their country.

Over the past decade, their Brexit fever has packed the Commons with Europhobes. These respectable law and order-minded patriots chose a dishonest, disreputable, disgrace of a man for prime minister, who will trash their constitution, mislead their monarch, and disrespect their judges to use “any means necessary” to get anything he wants. These ordinary people have turned into wreckers of what they used to hold dearest.

More hyperbole than hard cash, many announcements crumble under scrutiny – not 40 new hospitals but refurbishment for six

Observers ask if this party is falling apart in front of our eyes: expelling its MPs, pursuing a no-deal Brexit whose catastrophic effects would render the party unelectable for ever. If they only knew it, the Benn Act – preventing a no-deal crashout at the end of next month – saves them from themselves. Some of the 21 banished will not be kept away: Alistair Burt, Dominic Grieve and David Gauke brave the hissing. Any moderates here stay quiet, expect for one businessman tapping me on the shoulder, despairing at what no deal would do to his company. He handed me a paper. I was amazed to find a timeline of the rise of the Nazis. “That’s how Hitler did it, used the constitution step by step,” he murmured. Even the moderates are extreme.

Nothing augurs well for Boris Johnson – his bounce declining, caught in a pincer between Nigel Farage and an electorate that has for two years now swung away from Brexit. Long-term demographics may sink the party, with no decent victory since 1987. The flight of the young was spelled out brutally by David Willetts, chair of the Resolution Foundation. He found that only 8% of women under 35 would vote Tory. The age at which people vote Tory is rising fast – over 49s in 2017, now only a majority of those over 51. Age has outstripped class in determining voting habits. “How to win back younger voters?” they were asking. You can’t, was the conclusion. Because those in their 20s are worse off than their parents, not home owners, spending a third of their income on rents, stuck in insecure gig jobs, young parents crippled by childcare costs. Socially liberal, 20% ethnically diverse, deeply concerned about the climate crisis, they are ignored here. They are remainers and they will not be coming back. Best news for the Tories is the Electoral Reform Society reporting that 9.4 million are missing from the electoral register, mostly the young and renters: David Cameron stopped households and colleges registering them automatically, knowing the young are the enemy. Sorrowfully, the chair of Cameron’s former Witney Young Conservatives rose to say he had only four members.

A homeless man on the streets of Manchester, January 2017. Photograph: Christopher Furlong/Getty Images

After a decade of the most savage erosion of every service, the pre-election spending announced by the chancellor will not begin to repair the damage. More hyperbole than hard cash, many announcements crumble under scrutiny – not 40 new hospitals but refurbishment for six. “A relatively gradual increase in spending,” said the Institute for Fiscal Studies. Welcome, yes, but Sajid Javid’s offer of “a decade of renewal” will be greeted with wry disbelief, too late to change public perceptions when voters see the threadbare services around them.

Non-stop repetition of “one nation” Conservatism only reminds people how deeply this party has riven the country. Matching Labour’s “national living wage” was an eye-catching political necessity. But the chancellor’s “Brexit red tape challenge” against “overbearing bureaucracy” will sound a klaxon about plans for a post-Brexit removal of protections for workers, food, finance and consumer safety. Everything else is forgotten, the £37bn taken out of benefits gone for ever, as universal credit keeps tipping more families into penury; with child poverty approaching 40%, unmatched since the war.

Taking a breather from the fetid airlessness of this conference where all intellectual oxygen has been sucked out by “Get Brexit done”, I found Coffee4Craig, a small haven for the homeless, open two hours an evening for food, clothes and advice. Risha Lancaster opened it when her brother died on the streets from a heroin overdose. Among the old-timers, such as the woman in the wheelchair who comes for supper every night, she is alarmed to find so many more newcomers: she tries to divert them towards early help. “They get beaten up, everything stolen, especially shoes and ID. Everything spirals out of control.”

The five-week wait for universal credit, along with benefits sanctions, tips many on to the street. “There’s nowhere to send them for mental health, so many addiction services shut down. There’s no beds.” Several have stumbled in to die here, turned out by hospitals. Here is the 54-year-old woman in a flowery blouse thrown out by her landlord, and a live-in chef sacked with no benefits for rent. “Not the council’s fault, after all the cuts to their funds. They do all they can.”

The end of austerity will be a long time arriving here, if ever. Rough sleepers are only the most visible sign of the disintegration of all key services – from housing to A&E waiting times, and benefit levels that no longer keep working families’ heads above poverty. None of this is anywhere on Johnson’s one nation horizon.

He may think spaffing some last-minute cash has shot Labour’s fox. I doubt many voters will think austerity is over until there are no homeless in their supermarket doorways, until they can get a GP appointment, schools stop begging for pens, and the government takes the climate emergency seriously – virtually unmentioned here. Brexit stirs strong passions, but come an election the state of the nation counts for more – and the Tories will have no cover for their abysmal decade of strife and decay.

• Polly Toynbee is a Guardian columnist