In January this year, Germany's vice-chancellor Sigmar Gabriel gave an uncharacteristically candid interview for a European politician. 'Salafist mosques must be banned, communities dissolved, and the preachers should be expelled as soon as possible', he told Der Spiegel. 'If we are serious about the fight against Islamism and terrorism, then it must also be a cultural fight.'

Gabriel made his declaration two weeks after a lorry had been driven through a Christmas market in Berlin, killing twelve people. The perpetrator, Anis Amri, was revealed to have links to a radical Salafist preacher in the town of Hildesheim. Since Gabriel's interview there have been three more major Islamist attacks in western Europe - Manchester, Borough Market and Barcelona - and Salafism has been an influence in each one. So much for taking the fight seriously.

One wonders what, if anything, will spur the West into confronting Salafism, because to Berlin, Manchester, Borough Market and Barcelona one can also add Madrid (2004),Toulouse (2012), Paris (2015) and Brussels (2016). That's an awful lot of dead at the hands of one ideology.

It's a shame, for example, that Amber Rudd doesn't apply the same rigorous approach to Salafism as she does to National Action, the far-right group that she outlawed in December 2016 and which made the headlines on Tuesday when police arrested four member of the British army for alleged membership. In explaining her reasons for making it a criminal offence to belong to a group which praised the killer of MP Jo Cox, the Home Secretary said it 'stirs up hatred, glorifies violence and promotes a vile ideology...it has absolutely no place in a Britain that works for everyone.'

It is indeed a vile ideology but then what should one make of Salafism? As Haras Rafiq, chief executive of the anti-extremism think-tank Quilliam, said of the Manchester suicide bomber:

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'Through his father, through his connections, through the mosque, he has been absorbing Salafi ideology and theology'.

Salafism has inspired the global jihad that has killed tens of thousands of Muslims and non-Muslims this century; it was espoused by Osama Bin Laden, who was schooled in its ideology by Ayman al-Zawahiri, the current leader of Al-Qaeda.

Many Salafists are neither violent nor political and live their lives as if they were companions of the Prophet Mohammed in the Seventh Century. Known as Quietests, they denounce Islamist attacks in Europe and, after the murder of an elderly priest in his Normandy church last year, French Salafists handed out leaflets in which they called the killing an 'ignoble' act and emphasised that they 'advocate an authentic Islam...it's always humanity which prevails'.

Similar leaflets denouncing Isis and Al-Qaeda have been distributed outside London Underground stations. But what the literature doesn't mention is that Salafism seeks to purify Islam of Western influence. Europeans are regarded as heathens and Muslims who don't subscribe to their ancient interpretation of Islam are deviants. As the former White House security advisor Quintan Wiktorowicz wrote in 'Anatomy of the Salafai Movement':

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'The most dangerous challenge to pure Islam, from the Salafi perspective, is the application of human intellect and logic...there is no room for interpretive differences or religious pluralism.'

Quietests are Salafism's missionaries and their puritanical proselytising in Europe is poisoning thousands of impressionable young Muslims. Gilles Kepel, an Islamic scholar in France, first identified the emergence of Salafism in Europe 20 years ago and in his 2004 book, The War for Muslim Minds, he described what happened when a non-violent Salafist Imam arrived in a French inner-city mosque. 'Problems related to veiling often arise in nearby secondary schools in the following weeks and months,' he wrote. 'The new preacher's injunctions galvanise young male zealots, who reinforce his influence by applying social pressure on the young women in the neighbourhood'.

The problem has worsened in recent years and a book published last month in France showed the extent of the Islamification within some French schools. In Principal or Imam, a former headmaster in Marseille describes how swimming lessons, dress codes, the theory of evolution and school dinners have all become contentious issues since the turn of the century. Who is to blame? Salafists, reports Le Figaro, which, in an interview last week with the head of Marseille's education authority, reported that 'they wait at the gates of school and offer to help with [pupils'] homework.'

But the greatest menace to be found in European mosques are the 'Jihadists', the new breed of Salafist whose prominence within the movement has grown on the back of Al-Qaeda's exploits. Jihadists are adept at exploiting the naivety of young Quietests, whose initial indoctrination encourages them to reject Western values. 'When you're in the state of such alienation you become easy prey to the jihadi guys who will feed you more savoury propaganda than the old propaganda of the Salafists who tell you to pray, fast and who are not taking action', explains Keppel, who adds that Salafism is 'against European democracy'.

This is what happened to the Kouachi brothers, who punished the staff of Charlie Hebdo for blasphemy, and to the young jihadists in Barcelona who fell under the spell of their local Salafist imam. They made the transition from Quietest to Jihadist because the two factions have a common theological DNA.

Also at danger from the Jihadists are other Muslims because Salafists are in effect Islamic Supremacists; those who interpret their religion differently are regarded as heretics, like the Shiite imam in Brussels, killed by a Salafist in 2012, or the elderly imam in Rochdale who was bludgeoned to death in 2016 by two British Salafists for being 'a magician'.

The uncompromising Salafism offers young Muslims sanctity and security in a Europe many regard as obsessed with secularism and sexual equality. Where the West is solipsist and weak, Salafism is strong and determined. It demands from its disciples self-discipline and self-sacrifice, asceticism over hedonism - an attractive philosophy to young men ardent for some desperate glory.

Its surge in popularity in recent years is staggering. There are now 120 Salafist mosques in France, 79 in Catalonia and well over 100 in Britain (Britain still has a tendency to talk about 'Wahhabism', a similar but not identical ideology to Salafism. But according to the Islamic academic Mohamed Bin Ali, 'as a rule, all Wahhabis are Salafis but not all Salafis are Wahhabis'.)

Sigmar Gabriel's warning about Salafism has so far gone unheeded, partly because secular Europe can't fathom religious fanaticism in the 21st century. Instead, the continent closes its eyes and covers its ears and hopes that an ideology antithetical to everything it stands for will eventually reform.

It won't. So before long Europe will have a choice to make: either get serious with the Islamic supremacists or submit to them.