As liberal greens and the right align in a burst of Alpine angst, calls to ‘batten down the hatches’ have been growing before Sunday’s referendum

Andreas Thommen relishes statistics. He fires them at visitors like a schoolboy showing off before a test: “350,000 foreigners come into Switzerland every day”; “every second, 1.2 sq metres of land is concreted over”; land is scarce because “two thirds of it is uninhabitable due to all our mountains and lakes”.

We’re sitting in his kitchen in Effingen, an hour north-east of Zurich, drinking tea made from herbs grown in his garden. A couple more stats: “Bangladesh is more densely populated than Switzerland” and “a Romanian doctor can earn 10 times more in Switzerland than at home”.

It is a surprise to find Thommen at “hüsli”, as he calls it, using the colloquial Swiss word for “home”, on the eve of a referendum on the future of Switzerland in which he has had such a big role. But, he explains, the campaign group to which he belongs, Ecopop – a 40-year-old pressure group formed by professors, environmental activists and feminists – has run out of money.

“We only had 300,000 Swiss francs [£199,000] in the first place,” he says. So there are no more resources left to hold a rally and the posters and flyers have long since been distributed.

Instead Thommen, Ecopop’s general secretary and the mayor of Effingen – a 700-year-old village of 600 people – has the more prosaic and pressing task of preparing for a council meeting that will decide on a new sewage treatment plant for the largely agricultural community in which he lives.

Ecopop has arguably already over-achieved, having sparked a passionate and often aggressive debate on immigration. It took the 1,500-member group years but finally, on Sunday, having gathered the 100,000 signatures necessary to force a vote, its initiative to cap the number of immigrants at 0.2% of the resident population, in order to safeguard natural resources, will be put to the test at the voting booth.

It will be the second anti-immigration referendum in Switzerland in just nine months, following a rightwing initiative to introduce quotas on EU citizens that, to the shock of much of Europe, voters supported by a wafer-thin margin in February. The first vote was proposed by the rightwing populist Swiss People’s party (SVP), which is fronted by political firebrand Christoph Blocher. This one, by contrast, is the work of leftist ecologists, who have been taunted with an array of nicknames from “Birkenstock fascists”to “eco nationalists”. Most prefer “green patriots” or in the case of Thommen – who wears Birkenstocks but angrily dismisses the nickname – “liberal greens”.

Thommen is the first to admit that his group is “on a par” with the SVP. Ecopop’s initiative has also ridden on the momentum created by the SVP’s vote and growing sympathy for the idea that, with a population now made up of 25% of foreigners, Switzerland needs to batten down the hatches.

“We both recognise how necessary it is to control immigration, but only we’ve had the guts to put a figure on it and to push for helping the developing world control its population. The SVP wasn’t prepared to go that far,” he says, referring to the second part of the Ecopop initiative under which 10% of the nation’s development budget would be ploughed into funding family planning in the developing world.

He seems unconcerned that the Ecopop initiative has garnered so much support from the far right, but insists Ecopop is not racist and “the Swiss are not racist – we don’t have ghettoes like in France. Foreigners are integrated here. The founder of Swatch was Lebanese, you know.”

Ecopop’s proposal is one of three on the ballot paper for 5 million Swiss voters to decide on. The others are an initiative by a small group of radical rightwing outsiders that would require the Swiss National Bank to hold a fifth of its assets in gold within five years as well as bring home most of its gold currently held in foreign vaults, and the third proposes the abolition of the flat tax system under which wealthy foreigners, such as German Formula 1 driver Michael Schumacher and Swedish Ikea founder Ingvar Kamprad, have enjoyed huge benefits.

There appears to be a common theme. So why is Switzerland battening down the hatches? “Switzerland has been one of the most open countries in the world,” says Daniel Binswanger, editor of Das Magazin. “How many other countries are made up of 25% of foreigners? But that huge openness has been viewed with increasing ambiguity since the 60s and 70s. So far, the political authorities have been able to navigate these contradictions, but we now might be hitting a limit.”

Nonetheless it is hard to understand what has prompted this sudden bout of Alpine angst. Switzerland has the highest nominal wealth per adult in the world, enjoys one of the world’s highest life expectancy rates, and, despite the high cost of living, ranks as one of the best places to live. “I know we have it good,” says Thommen, looking out of his window at the elegant houses of his village with their woodpiles and flower boxes, as well as to an Ecopop campaign poster hanging on a lamppost. “And I know I have it good. And I’d like it to stay that way.”

Binswanger describes this as a “kind of imaginary pain”. In terms of wages and living standards, he says, “we’re doing rather fine. Life is very satisfactory.” What has changed is that foreigners are increasingly doing better than the Swiss themselves. “Nowadays the average professional qualification of an immigrant is higher than that of the average qualification of a Swiss citizen and, psychologically, this is a problem.”

The proposal to abolish tax privileges for foreigners is part of the same debate. “Even Swiss billionaires are asking themselves why they pay high taxes when their rich foreign neighbour pays hardly any and lives in a bigger house,” Binswanger adds.

The words ecopoppers repeatedly use to express their dissatisfaction are zubetonierung (being concreted over), dichtestress (the stress of living in close proximity to others) and the self-explanatory “Alpen Hong Kong”.

“We are slowly being concreted over,” says Thommen. “We’re running out of space. Eighty to 100,000 foreigners come here every year. We’re a nation of just over 8 million. Apply that figure to Britain and it would be the equivalent of a million a year.”

Mario, an Italian from Piacenza in northern Italy, is the second generation of his family to work in Switzerland, a so-called secondi. “I earn considerably less than a Swiss employee would earn. That’s okay with me, as when I go back to Italy my living costs are lower and I’m glad to have the job,” he tells the Observer in a telephone interview. “But I’d like to see what happened if they started putting a cap on immigration.”

He says he had not heard about the referendum. “I’m too busy working, though now I know it doesn’t surprise me, though neither does it exactly make me feel very valued, even though I actually feel very Swiss myself. And this will surely increase the feeling among foreigners here that they should watch their backs.”

Many Swiss commentators have accused Ecopop of pandering – not unlike the far right – to an unhealthy nostalgia for the past.

“The impression being given is that the postwar Switzerland we knew and loved, that recognised the existential necessity of international exchange but also ... valued its independence and sovereignty, is becoming lost to us,” Hannes Nussbaumer wrote recently in the Berner Zeitung. “Switzerland finds itself in an era of change, driven mainly by globalisation of which [the country is] a beneficiary, but we only have such prosperity, stability and almost 100% employment thanks to our international outlook.” Switzerland ignores that fact at its peril, he says.

Whether Ecopop does well at the polls or not, the Hungarian-Swiss author Nadj Abonji is increasingly anxious about the tone of the debate. She believes that Thommen’s ecopoppers, together with their rightwing bedfellows the SVP, might well have set the agenda for some time to come. “I fear the next years will continue in a similar vein – visionless, pusillanimous, either openly or covertly racist, in a country that doesn’t have a clue about poverty or population density.”