The Swedish and German authorities say they have never encountered anything like it: groups of men encircling then molesting women in large public gatherings. It happened in Cologne and Stockholm, but is it really unprecedented? Ivar Arpi argues in the new Spectator that it may well be connected to a phenomenon called ‘taharrush gamea’, a form of group harassment previously seen in Egypt.

So what is taharrush gamea, and should Western police be worried? Here’s what we know.

‘Taharrush’ means sexual harassment – it’s a relatively modern word, which political scholar As'ad Abukhalil says dates back to at least the 1950s. ‘Gamea’ just means ‘collective’. Taharrush gamea came to attention in Egypt in 2005, when female protesters against the Mubarak government were sexually assaulted by plain-clothes policemen. Many subsequent cases were political in nature, but not all: as Mariam Kirollos writes, in 2006 ‘Egyptian bloggers reported cases of group sexual assault in downtown Cairo, where large groups of men groped veiled and unveiled women, and in some cases ripped their clothes off’. There were also cases of rape.

After the revolution in 2011, the attacks became more organised. The following year, volunteer groups of men began patrolling parts of Cairo to protect women from collective assaults. These became horribly frequent: in summer 2013, in the ten days around the time President Morsi was deposed, there were 186 documented cases of mob harassment, assault and rape.

Heather McRobie, a journalist and academic previously based in Egypt, says some of the assaults in Tahrir Square were co-ordinated political attacks – the authorities wanted to make the square unsafe, and to drive out women. ‘Some were also opportunistic, like at a festival – lots of people, easy to get lost in the crowd, and men can take advantage of that situation.’

Some news reports have said vaguely that this is an ‘Arab phenomenon’ which is ‘recognized in Egypt’. What about other countries? This is pertinent since Egyptians are not especially well-represented among migrants in Germany and Sweden. But outside Egypt – say, in Afghanistan and Syria – reports of this kind of assault are harder to find. According to McRobie, Egypt was exceptional in the region: there are no similar accounts from Tunisia in 2011-13, for instance – although that country also has serious problems with sexual harassment and assault.

So based on what we actually know, the link between the Cologne and Sweden stories and recent Middle Eastern history is not as clear-cut as has been suggested. McRobie says: ‘it would be disingenuous to pretend that violence against women isn't an issue in the Middle East/Arab world – the whole region has a terrible track record.’ At the same time, she adds, violence against women is also at epidemic levels in Western societies – and ‘there is a danger that the real tragedy of violence against women is being instrumentalised by those who do not sincerely care about sexual violence, but only feign concern in order to propagate racism’.

There are other possible factors in the Cologne and Sweden attacks: the sociologist Valerie Hudson has observed that male migrants greatly outnumber female ones – a population imbalance strongly associated with increased crime.

Taharrush gamea shouldn’t be ruled out as a factor; but given what we know so far, some of the news reporting and the social media hubbub seems a little over-excited.