Warning: Lawyer Nazir Afzal is concerned that the influx of young, male migrants risks tipping the whole balance of European society

As the song says, it’s raining men. But it is no cause for hallelujahs. Far from it — the influx of young, male migrants from the Middle East and North Africa risks tipping the whole balance of European society.

A disproportionate majority of the immigrants from Syria, Iraq and Libya are unmarried young men, many of them under 18, travelling without family members.

Restless and rootless, those lone boys are part of a very alarming trend. Studies consistently show that communities with a predominance of single males are more prone to aggression and, in particular, sexual violence.

We had a grim warning of what this means on New Year’s Eve, when gangs of hundreds of young men of North African or Middle Eastern appearance, many of them apparently drunk and speaking Arabic, crowded around female revellers in Cologne and Hamburg, and robbed them while committing vile sexual assaults.

The victims spoke of being surrounded by 20 or 30 men at a time who pressed against them so hard they were unable to move or fight back, let alone escape. While some men groped the women, others snatched bags, phones and purses.

The assaults were terrifying and degrading, and many of the women felt too defiled even to be able to report the robberies for several days. When they did, the police initially did not appear to take them seriously.

It is a shocking development, but one that does not altogether surprise me. Male-dominated migration is a problem we need to be talking about.

Many readers might assume that in warzones such as Syria and Iraq, it is women and children who are most at risk. But it’s the boys, from the age of about eight and up, who are most likely to be turned by Islamic State into ‘cub’ fighters — or killed. That’s why they are so vulnerable, and so intent on reaching safety out of the country.

In Europe last year, more than a million migrants swept in — up to 400 per cent more than arrived the previous year. Nearly all came across the Mediterranean from Africa or the Aegean coast, and according to figures released by the United Nations refugee agency UNHCR, half were Syrians, fleeing the war.

Another 20 per cent were Afghans, and 7 per cent Iraqis. The majority were brought in by people-smugglers, whose highly organised operations were worth an estimated $1 billion (£680 million) last year alone.

This problem is familiar from nightly news coverage. But what the reports have failed to address is the damage that can be done to societies that prize sexual equality, and a peaceful, stable way of life, when so many migrants are young men.

Hundreds of people gather in front of Cologne's main railway station, where disorder broke out last week and groups of 'Arab or North African' men attacked dozens of women

Groups of revellers gather in the city centre during the celebrations last week which quickly turned to chaos

According to Unicef, more than one in five of the migrants is under 18. Of those youngsters on their own, about 90 per cent will be male. In Sweden, which welcomed nearly 28,000 migrants in the first nine months of last year, 71 per cent of all applicants for asylum were male.

On any given day in 2015, about 90 unaccompanied males younger than 18 came in, compared with just eight unaccompanied females.

The assaults were terrifying and degrading, and many of the women felt too defiled even to be able to report the robberies for several days. Lawyer Nazir Afzal

As a result, among 16- and 17-year-olds across Sweden as a whole, the male-to-female ratio is far more skewed even than in China at the height of its one-child policy, only recently relaxed.

As a fascinating article by Valerie Hudson on the Politico website reveals, 18,615 males aged 16 and 17 entered Sweden in the past year, compared with just 2,555 females of the same age. Added to the existing population of the same age, it means there are now 121,914 males in Sweden aged 16 or 17, compared with 99,079 girls — a 123:100 male-to-female ratio. In China, the male to female ratio in the same age group is approximately 117:100.

Hudson argues that it will not take long for Sweden’s broader young adult population to be similarly skewed, assuming the trend in migrant arrivals continues as expected beyond this year.

And it is not just Sweden. By September last year in Greece, the UNHCR believes, some 730,000 migrants had arrived on flotillas of boats, of whom more than a quarter were under 18. Again, the great majority were male.

People have not wanted to talk about this, but we have here a recipe for disaster. When more and more unaccompanied teenage males upset the sex ratio balance, insurmountable problems are created. As a former Chief Prosecutor for the Crown Prosecution Service, I have been warning for a long time that people bring cultural baggage with them from their old lives into their new environment.

A group of men set off fireworks during the New Year's Eve celebrations in Cologne last week. Police say groups of men (not pictured) were responsible for coordinated attacks on women

If they come from a country where women do not enjoy the same rights as men, or where homophobia is rampant, they will bring those moral codes with them. We have to be prepared for that — to acknowledge it, and to fight it. We can’t just pretend it isn’t happening.

Men who don’t have a potential wife are more likely to get involved in crime, and less likely ever to become part of a family. They join gangs, they become rebellious and disaffected, and they start to behave as though the laws of their adopted home do not apply to them — and then we see appalling scenes such as those in Germany on New Year’s Eve.

As the mayor of Cologne has said, we have to be cautious about assuming the perpetrators are migrants, until we have evidence. But what is certain is that where you have large numbers of young men together anywhere, they will exhibit a herd mentality.

They feel they can do anything they want to anyone they outnumber, particularly women, who are extremely vulnerable in such an environment.

If they come from a country where women do not enjoy the same rights as men, or where homophobia is rampant, they will bring those moral codes with them. Lawyer Nazir Afzal

Britain has coped well with migrants in the past. The difference, however, with immigration in the Sixties and Seventies is that very often people came as families, with opportunities for work. My parents immigrated here from the north-west frontier of Pakistan in 1961, and I was born the following year. My family had worked with the British Army in India, and they carried on in that line of business, providing catering services to the forces in Northern Ireland during the Seventies.

What we have now is a very different situation. Canada’s new liberal government has already taken action, with a ruling that starting in 2016, only women and families, and unaccompanied male minors, should be permitted entry. It means that older teen and young adult men will not be allowed in.

The British Government has adopted another partial solution, aiming to bring in only the most vulnerable from the refugee camps themselves. But these steps do not provide a complete answer.

The majority of young men arriving on European shores are unaccompanied, and when they disperse into existing communities they are likely to live with others of a similar background.

Education is the key, but my concern is that the resources are not there. More importantly, we lack the will to use what money we do have sensibly. People already claim, for example, that if there is to be education about honour killings and forced marriage, it must involve every child in the country, regardless of their race or background. This is nonsense.

And sadly, because of political correctness, and because some individuals and institutions are scared of seeming racist, we allow terrible abuses to happen in plain sight.

To the fury of many Germans, it has emerged that it took three days for the Cologne assaults to be taken seriously by the police, and initially they were largely ignored by the German news media.

In Britain, too, several predatory, mainly Asian, grooming gangs who targeted white girls in towns such as Rotherham were allowed to continue for years while the authorities hesitated to bring them to book.

During more than two decades at the CPS, first in London, and then in north-west England, I was responsible for bringing members of such gangs to justice. I was also the national lead against both honour killings and forced marriages.

At all times I aimed never to show neither fear nor favour, no matter the class, status, ethnicity or religion of any suspects. It was my compilation of evidence, for instance, that helped bring to justice the high-profile TV presenter Stuart Hall on serious charges of child abuse.

It is our duty to be concerned about the safety of everyone, and that, of course, includes people who come here as migrants.

But as a matter of policy we should be looking at bringing more women and children as part of the 20,000 we have agreed to take over the next four to five years, rather than just accepting them on the basis of first-come-first-served.