As Theresa May faces her first EU summit today, the other 27 member states will be eyeing her up. Will she approach them in the fearsome tones of her party conference speech, or is there more emollience beneath that inscrutable coldness? On her real views, we are as much in the dark as they.

The message she has chosen to send out today is “no second referendum”, an opening statement of the blindingly obvious. Number 10 adds the banality that she wants “a strong UK as a partner of a strong EU”, but the 27 see Britain – with her party to blame – as feckless wreckers who will leave both sides weaker.

Leaders she meets across the table have so far have been equally intransigent: if Britain wants to opt out of fundamental obligations, it can’t opt into fundamental rights. Irritation built up over years at the UK demanding exceptional treatment had Luxembourg’s prime minister, Xavier Bettel, echoing the rest: “Before they were in, and they had many opt-outs. Now they want to be out, with many opt-ins.”

Every soundbite, and signal, from every leader over recent weeks knocks down British wishful thinking that we can stay in the single market and the customs union while denying free movement of people. Or that we can forge special sector-by-sector trade deals for our most prized industries – passporting rights for finance and good deals for our cars or pharmaceuticals. Instead, the French, Germans and Irish are busy trying to woo those businesses to relocate with them, and why wouldn’t they?

Brexit extremists Liam Fox and David Davis, alarmingly in charge on our side, casually shrug. “Never fear, we’ll strike better deals from outside”, but Boris Johnson’s suggestion that these will have “possibly greater value” is knocked down by EU leaders warning that Britain must be clearly seen to end up worse off.

Meanwhile, Brexit ministers brazenly brief against their chancellor, as Philip Hammond struggles to keep hold of some sense of reality about the vital economic importance of our main trading zone. Unsurprisingly, Mrs May tonight is relegated to a brief statement in “any other business” over coffee.

Hard Brexit, a slammed door, increasingly looks inevitable to many gloomy ex-remainers. The four freedoms are set in stone, with no leeway for a British freedom to be exceptional.

There is only one way out of this. The British people may decide the cost is too high. Before anything has happened yet, they can see how the prospect of hard Brexit is already causing serious damage. The pound plunging by 17% is a national disaster, predicted to fall further: only those who supported Brexit whistle in the dark, pretending it’s good news. It will help a few manufacturers and Bond Street retailers of luxury goods, but our precarious over-dependence on imports means steep price rises ahead in petrol and food are rather more important than cheaper Burberry handbags. We may decry an unbalanced reliance on the finance industry, but wrecking it before building up anything else will leave a chasm in treasury revenues, more cuts, more job losses.

People aren’t stupid. They may want less immigration – but not at any cost. The stupidity was a referendum campaign that boiled everything down to that one issue. But people don’t think just one thing, they have many views and priorities: when the facts change, they tend to change their minds.

The latest Ipsos Mori poll shows a sudden plunge in public confidence over the economy. Only 24% expect the economy to improve while 53% think it will worsen (up from 37% in September). Do they think the effect of Britain voting to leave the EU will make their personal standard of living better or worse? Only 24% say better, while 49% say worse – a big shift, says Ipsos Mori’s Ben Page.

Is Regrexit beginning? He says the Marmite price war brought it home to people that food prices will rise sharply. With 55% saying devaluation is bad for Britain, people get it, despite all the Brexit media denying it. As with the vote, the young are more worried than the old, the ABC1s more worried than the C2DEs, but the shift runs all through the Brexit supporters too. With this economic anxiety, Theresa May’s personal rating is drifting already, down six points to a still high 48% satisfied with her. (The Tories are at 47%, Labour 29%.)

It’s worth noting that the British Election Study finds that many who voted leave didn’t actually think it would happen. That suggests those who thought they were just protesting may change their minds, finding the economic price too high. Other polls show opinion on the move: ComRes for the Independent on Sunday finds people think a good trade deal with the EU is more important than cutting immigration. Now 49% put trade ahead, while 39% still prioritise immigration. When May in her conference speech said: “We are not leaving the European Union only to give up control of immigration again,” she may find quite soon she too has freedom to change her mind: free movement might be a price worth paying for staying in the single market and the customs union.

Open Britain, campaigning for staying in the single market, points out that very little has happened yet to change people’s mind. So how much further may public opinion shift when the Brexit effect really bites?

• This article was amended on 21 October 2016. An earlier version said incorrectly that the British Election Study found that most who voted leave didn’t actually think it would happen.