The error of Emma Kelty, the one that cost the British adventurer her brave life on the banks of the Amazon, was a failing all too common in Europeans: she had too much good faith. Raised in comfort and educated in compassion, Kelty had little concept of the savagery that lurks in some souls. Displaying a mix of naivety and conceit, she ignored warnings from villagers and went on her way, even posting a joke on social media mocking the locals' concern for her welfare. Two days later she was murdered by a gang of 'water rats', young men with no regard for human life. What happened to Kelty is little different from what has been happening to Europe in recent years. The same naivety and conceit afflicts our leaders who struggle to understand that there are, living among us, a great many people who want to cause us harm.
In an interview with a French newspaper at the weekend the German feminist and journalist, Alice Schwarzer, explained that Angela Merkel's greatest mistake was that 'even before the migrant crisis she had not understood the difference between Islam and Islamism, between the religion and the political ideology'. Schwarzer blamed Merkel's failure to grasp the crucial difference on the fact she's the daughter of a pastor, who preached tolerance and kindness. The same criticism can be levelled at Theresa May, whose father was a vicar, and no doubt delivered sermons on similar themes. The PM, like the German Chancellor, seems to believe that in the end the Islamists will come round to our way of thinking and embrace our set of values.
They should read a book by a French reporter called David Thomson to better understand why their hope may be dangerously misplaced. Called Les Revenants [The Undead], the title is a nod to the French jihadists who fought for the Islamic State before returning home. It is a disturbing but masterly work of research by a journalist who, in his own words, was 'humiliated' on television in 2014 for daring to suggest events in Syria would cause terrorist blowback in France.
There are hundreds of former Islamic State fighters now back in the West; at least 750, according to Europol Director Rob Wainwright, although as many as 2,500 European-born fighters are likely to be in 'various stages of returning'. A few return claiming that they have renounced Jihad, like the Canadian who breezily dismissed his time fighting for Islamic State as something 'that’s behind me, we all do things that we regret'.
But of the numerous returnees Thomson interviewed, the majority were unrepentant and only one, Zoubeir, has co-operated with the authorities to promote an anti-Islamist message within his local community. 'They're still jihadists,' Zoubeir said of his former comrades. 'That's the reason why most aren't prepared to give evidence against others...because they consider France impious, an enemy of Islam, which fights their brothers'.
Thomson's book also reveals the contempt with which the Islamists regard the West's attempts to deradicalise them. 'I don't see how you can de-radicalise these people because they don't see themselves as radicals, but as Muslims conforming to what they follow, which is the Koran', said Zoubeir.
A female Islamist, Lena, who told Thomson that the murder of the Charlie Hebdo cartoonists was one of the most 'beautiful' days of her life, explained that the West doesn't understand the depth of their faith. 'It's funny', she said. 'They talk to us as if we're life's losers...but for me, deradicalisation is just some fancy new word they've dreamt up'.
Another woman, Safya, described losing patience with her intelligence service interrogators upon her return to France. Why wouldn't she condemn Islamic State's beheading of hostages? they asked repeatedly. 'It's in the Sharia,' she kept telling them. 'I don't have to be for or against: Sharia is Sharia. Full-stop!'
Many of the Frenchmen who fought for Islamic State remain in prison. Although that in itself is a cause for concern. Prison is described by Thomson as a jihadist's university - as it is in across Europe - where Allah's battle-hardened warriors can radicalise impressionable young Muslims serving time for petty crime. It was reported this week that in Belgian prison inmates now receive letters under their cell doors inviting them to join Isis.
For the moment, Europe retains blind faith in its approach. 'In the long term, authorities and local communities need to work together to resocialise or integrate returnees into society', said a recent report published by the European Commission’s Radicalization Awareness Network. Alice Bah Kuhnke, Sweden's minister of Culture and Democracy, said something similar earlier this year, declaring the need to have 'structures locally, such as social services, around our country to integrate them back into our democratic society'.
Has it occurred to people like Kuhnke that they may not want to be re-integrated, that no number of well-meaning social initiatives will bring them back into a secular culture they despise?
Indeed, the greatest threat posed by the returning jihadists isn't so much what they might do but what they might say, radicalising young and impressionable Muslims who never made the trip to Syria or Iraq. 'We are even more concerned by that phenomenon right now', admitted Rob Wainwright in a recent interview.
Zoubeir shared a cell with such a young man when he was imprisoned upon his return to France. His cellmate was still a teenager, unknown to the French police when he was arrested by the Turkish authorities in 2015 on way to Syria. He rose at 4am to pray and scolded Zoubeir for listening to music. It wasn't righteous, he said, unlike martyrdom. Zoubeir considered his cellmate more fanatical than the men he'd fought with in Syria because he felt he had to prove himself. Nonetheless ,in March 2016 the young man convinced a French judge he was no longer radicalised but was 'a Muslim grounded in the values of mercy and goodness'.
Zoubeir's cellmate was called Adel Kermiche, and not long after his release he and another teenage Islamist walked into a quiet Normandy church and slit the throat of the priest. The judge had been warned by prosecutors not to release Kermiche but the advice was ignored. Naivety and conceit can be a fatal concoction.