Waiting at the bus stop with their bags are three Syrian men fed up with Swedish hospitality. Five minutes ago, they walked out of a charity-run migrants' hostel surrounded by trees in a pretty tourist town, an hour's drive from the country's second city of Gothenburg.

'We refuse to stay there,' says 29-year-old Maher Al-Saleh, as he stands defiantly on the roadside. 'The bedrooms are small, it's dirty, and they serve pasta every night, which we don't like. It is run like a Christian prison, with prayers before meals. We are Muslims.'

This may sound rather ungrateful. Maher and his two friends, Mahamed, 22, and Mahmood, 38, came to Sweden after taking this summer's well-trodden route to Europe from the Middle East, via Turkey. On reaching Germany, they discovered that the waiting time to claim asylum was running into months.

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Ultra-liberal: Sweden has a reputation for welcoming any foreigner, and handing out generous benefits

So, last month, they boarded a ferry to ultra-liberal Sweden, which has a reputation for welcoming any foreigner who knocks, and handing out generous taxpayer-funded benefits.

Of course, like the 100,000 other incomers to this country of just 9.5 million people this year, Maher's group was let in, and given a place to stay. But there's a problem: by Christmas, another 90,000 are expected to try to enter Sweden, leaving conflict in Syria, Afghanistan and Iraq, as well as poverty-plagued parts of Africa.

Put the word 'asylum' in Arabic into a smartphone search engine and 'Sweden' comes out as the top result. Its population is the fastest-growing in the EU. The country accepts one in seven migrants entering Europe — more per capita than any other state.

In 15 years' time, demographers say, indigenous Swedes will be in a minority because the men who arrive are allowed to send home for wives and children, who in turn will have their own children.

The Swedish economist Tino Sanandaji, who himself has an Iranian-Kurdish background, recently described what's happening in Sweden as 'quite disastrous'. He said: 'This is an irreversible social experiment that no wealthy state has ever attempted. There are almost no ideas or visions over how this can be solved.

'You can't combine open borders with a welfare state. If you offer generous benefits, and anyone can come and use these benefits, a very large number of people will try to do that. It's just mathematically impossible for a small country like Sweden to fund that.'

Migrants are escorted by police officers as they arrive in Sweden by train after crossing the border with Denmark

Indeed, the truth is that despite its oh-so liberal reputation for warmly welcoming incomers, the attitudes of ordinary Swedes about immigration are changing by the hour.

This week, the Swedish Prime Minister Stefan Lofven admitted that his country faced a crisis. On Thursday, it reinstated border controls, carrying out identity checks on passengers travelling by train across the strait from Denmark, and those arriving at ferry terminals in the south, to 'maintain public order'.

Concerns are growing over security, amid fears Sweden could pay a terrible price for its indiscriminate welcome of people whose identities and backgrounds have not been adequately checked.

The country is running out of beds, the Migration Minister Morgan Johansson has warned, and the Swedish people — who already pay the highest taxes in Europe — have even been told their holiday homes may be seized to help out.

The Swedes put themselves in this situation. They have pursued a very lenient immigration policy for years and they are to blame for the swamp they are in

The Swedish furniture store chain Ikea has almost sold out of mattresses because so many are needed for migrants' accommodation in hotels, sports halls, ski chalets, summer schools, military camps, museums, theme parks — and the new tented villages beginning to dot the country.

As for paying for all the newcomers, Sweden has dipped into part of its overseas aid budget but has also gone cap in hand to the EU, begging for emergency funding to cope with the ever-growing influx. In what many view as an act of rank hypocrisy, this week the government even asked other EU countries with tougher border controls to take migrants off their hands.

Neighbouring Denmark refused. As its Immigration Minister Inger Stojberg bluntly explained: 'The Swedes put themselves in this situation. They have pursued a very lenient immigration policy for years and they are to blame for the swamp they are in.'

It was back in 1975 that the Swedish parliament decided that the country should become multicultural. The population then stood at eight million — virtually all ethnic Swedes — but its people had a proud history of offering help to outsiders.

A new ultra-liberal immigration policy was pursued enthusiastically by the ruling Left-wing Social Democrats for the next four decades. Sweden seized the moral high- ground in Europe by offering shelter to anyone in the world. Those who criticised the radical plan were shouted down as racist, as Sweden became the EU's citadel of political correctness.

But today Sweden faces uncomfortable questions about the kind of society it wants, or can afford, to be. At 16 per cent, the foreign-born proportion of its population is already higher than that of not only Germany and Great Britain, but also the U.S.

A group of migrants off an incoming train gather on the platform at the Swedish end of the bridge between Sweden and Denmark in Malmo Sweden

The Right-wing Sweden Democrats, an anti-immigration party, has quickly climbed to be the third largest in the polls thanks to support from Swedes who blame the migrants for rapidly rising crime rates and changing the country's culture.

This week, the party, which is backed by 25 per cent of Swedes, distributed controversial leaflets in Lesbos, the Greek island from which migrants arrive in rickety boats to get a toehold in Europe.

The message on the leaflets was stark. It read: 'There are no money, no jobs, and no homes left in Sweden. Migrants now only get tents and camp beds.

'Our society is falling apart. We have to borrow money to provide education and basic health care for our citizens. Due to decades of mass immigration, our previously safe country is not safe any more.

'Not only do we have a very high number of shootings and gang-related violence . . . but Sweden now has the second highest number of rape reports in the entire world.'

It went on: 'In Sweden, women and men are equal. Forced marriages and polygamy will never be accepted. Halal slaughter of animals, wearing the niqab or burqa in public places will be forbidden in our country.'

However emotive the leaflet's language, the fact is that life for all Swedes is changing irrevocably.

By the end of next year, income taxes are expected to be running at 60 per cent for the biggest earners, the highest in the world.

The Army and the Civil Contingencies' Agency, set up to manage disasters, has been drafted in to help with the arrivals. Citizens have been told to stock up on water and tinned food in case shops run short. And on the streets, there is an air of tension.

Police gather a group of migrants off a train at the Swedish end of the bridge between Sweden and Denmark

Of course, migrants cannot be blamed for all the ills befalling Sweden — far less, every crime. Yet this is undeniably a society under strain. Since 1975, violent crime and rapes, including gang rapes, have risen to an extraordinary high level (in politically correct Sweden official statistics do not give the ethnic background of attackers.)

Forty years ago, 421 rapes were reported to the police in Sweden annually. By 2010, according to a BBC report, police recorded the highest number of offences — about 63 per 100,000 inhabitants — of any force in Europe. That was the second highest in the world — surpassed only by Lesotho in southern Africa.

In 2014, according to the Gatestone Institute, a respected American think tank, the number of rapes had risen to 6,620, an increase of 1,472 per cent since 1975.

In August, a double murder in an Ikea store in Vasteras, a small city in central Sweden, sent shockwaves through the nation. The victims were ethnic Swedes, 55-year-old Carola Herlin and her 28-year-old son, Emil. Their attacker was a 36-year-old Eritrean migrant who confessed to the random killings, apparently carried out with knives seized from the store's kitchenware department.

Last month, there was another tragedy, in Trollhattan, a multicultural town, now home to hundreds of migrants, near Gothenburg.

Wearing a Darth Vader mask, a 21-year-old Swede called Anton Lundin Pettersson walked into a secondary school and stabbed a teacher with an Iraqi background, and then a 15-year-old pupil with the surname Hussan.

If you offer generous benefits, and anyone can come and use these benefits, a very large number of people will try to do that. It's just mathematically impossible for a small country like Sweden to fund that

The police, who shot Pettersson — he died later of his wounds — said he had targeted 'those with brown skins' in a racial attack.

Prime Minister Lofven visited the school within hours, but this did not prevent ordinary Swedes deluging him and his government with emails of protest that were later released through Freedom of Information requests. The emails reveal the mood of the moment. Mattias, a 43-year-old social worker and father of four, wrote: 'I am trying to explain to my children, aged six to 16, what is going on in Sweden. I want my kids to grow up here the way I did, without explosions, hand grenades, car fires, violence, rape, and murder at Ikea.

'All these things are happening due to the unchecked influx from abroad. You are creating a hidden hatred in Sweden. We are dissatisfied by the way immigration is handled.'

Another protester, Marcus, 21, who had voted for Mr Lofven's Social Democrats, said he was unhappy still to be living with his parents owing to the public housing shortage.

'As soon as an old person moves out, eight foreigners move in: they just bypass us young Swedish people waiting in line,' he complained.

'With all the rapes, robberies and murders going on, why aren't non-Swedes sent back to their countries when they commit crimes?'

Another writer, Laila, added: 'I was raised in a Stockholm suburb, but seven years ago we moved on because we couldn't take the dogs out in the evening due to non-Europeans driving on the pavements. If you didn't move, they would jump out of the car and hit you. If you called the police, they did nothing.

'When my brother told these men off, a lit rocket (the kind you use at New Year) appeared in his mailbox. You can imagine how loud the blast was.'

A group of migrants from arrive off a train at the Swedish end of the bridge between Sweden and Denmark

Even the normally reticent police have admitted that some parts of Sweden have become 'no-go' areas for them. As one official explained recently: 'Police, ambulances and the fire brigade are attacked by gangsters. There are a lot of firearms, handguns especially. The kids throw stones at them, too — there are more or less riots.'

According to Professor Sanandaji, the economist mentioned earlier, nearly half of the young immigrants who arrive will struggle to pass exams at school or get a job. They are likely to live in 'nice Swedish welfare ghettos', rely on benefits, and — sadly — play their part in boosting crime rates. A particular problem for the authorities is coping with the thousands of unaccompanied children who are turning up. It costs £80,000 a year to house, educate and feed each under-age migrant — and so far this year, 33,000 have arrived.

Nowhere is the impact of migration more visible than in Trelleborg, Sweden's southernmost town, a few hours by ferry across the sea from Germany. Last month, 1,900 young Eritreans, Afghans, Somalians and Iraqis claiming to be under 18 arrived after refusing to seek asylum in Germany because of lengthening waiting times for registration.

Here, and in nearby Malmo, Sweden's third biggest city, the authorities are struggling to cope. In Trelleborg, I found a 17-year-old Afghan, Mohsen Karimi and his four friends idly hanging around the town centre with scores of foreign youngsters. They took me to a big house, where they live off the main promenade, and explained they are given handsome pocket money of £160 a month, three free meals a day, as well as the use of bicycles.

Looking over his shoulder before posing for photographs, Mohsen said he had been told by the migration authorities not to talk to the Press, before adding with a grin: 'We want to be in Sweden because it is better than Germany. We arrived last month from there. I hope one day my family will join me, and we will be Swedish.'

Mohsen claims to be 17, but the authorities will never know for sure. The fact is that many of the so-called child migrants heading for Sweden are in fact adults, cynically pretending to be under 18 to get their asylum cases fast-tracked.

Swedish police gather a group of migrants off an incoming train in Malmo Sweden

This trick was highlighted by journalists who visited a migrant hostel in Malmo and took a picture of an Afghan youth, Ahmad Farid, who claimed to be 16. They put a stuffed polar bear doll in his arms, producing a photograph that was clearly of an adult man clutching a child's toy.

The photograph has since become a 'pin up' for groups campaigning against the refugee children 'fraud'.

The authorities refuse to do tests to determine their age, calling them invasive and an abuse of human rights, so they have no way of knowing who is an adult and who is not. In neighbouring Denmark, where the approach is tougher, they have found that 72 per cent of 'child refugees' are in fact adults. In Finland and Norway, the figure is 66 per cent.

Back in the small town of Munkedal, where I had met Maher marching out of his accommodation run by a church charity, I talk to the locals about the future of Sweden. Outside the supermarket, one man in his 50s shakes his head. 'Be careful where you go. It's unsafe,' he said. 'The other day there was an arson attack on a migrants' centre up the hill. People are getting angry and frightened.'

The attack, which left 14 migrants suffering from smoke inhalation, was one of scores on similar targets this summer as anti-immigrant sentiment grew. The Swedish authorities now try to keep the addresses of migrants' homes secret — although that is well-nigh impossible.

As for Maher, he left his home city of Dayr Az Zor, situated in the middle of Syria's civil war, to seek a better future. A bachelor and trained electrician with good English, he would seem the perfect candidate for a new life in Europe.

Yet despite his free accommodation and food, he seems dispirited by Sweden as a whole. 'They do not like us in Sweden any more. There are too many of us who have come. We have nothing to do but eat their food, and sleep. Perhaps I may go to Finland now.'