In his new book, Ed Husain takes the temperature of Muslim Britain by visiting mosques in ten cities across the UK at Friday prayers. There are 3.4 million British Muslims, divided by culture, theology and class as well as temperament, and many rarely attend Friday prayers since they are either working or not especially religious. But the small sample size does not stop Husain drawing sweeping conclusions. While his title alludes to V S Naipaul’s Among the Believers, Husain is unable to match the novelist’s magisterial prose or penetrating insights. Instead, his book careers painfully from the risible to the frankly sinister.

The error-strewn first page sets the tone. The Jewish orientalist Gottlieb William Leitner, the builder of Britain’s first proper place of Islamic worship (the Shah Jahan Mosque in Woking, which opened in 1889), was not a convert to Islam but to Anglicanism. Nor was the mosque named after a Mughal emperor but rather the Begum of Bhopal, Shah Jahan, who funded it. And it could not have been a Mughal ‘outpost’, since the British had deposed that dynasty in 1857.

Bigger themes are handled no better. In the wake of the Brexit vote, Husain asks, ‘if Britain could not tolerate white Christian Europeans, what is the fate of its Muslims?’ Speaking to a Bradford imam, he suggests three possibilities: ‘a religious war’, ‘self-deport or get deported’ or ‘modernise, integrate, and live in peace and harmony with all our neighbours and contribute to Western society’. Personally, I have enough confidence in my fellow citizens – Muslim and non-Muslim – to believe that deportation isn’t an option.

While in Bradford, armed with Alain de Botton’s The Consolations of Philosophy, he seeks to spread his wisdom. At a Muslim school in the city, he wants to ask questions but, he says, ‘I worry that the Socratic spirit may bring me harm here’. He visits the Darul Uloom seminary near Blackburn, which, he claims, lacks a broad curriculum in Islamic and Western intellectual history. Such a curriculum, he mentions, is being taught at Cambridge Muslim College, but he chooses not to visit there.

As a teenager, Husain joined the hardline Sunni group Hizb ut-Tahrir and now has the zeal of the recovering extremist. He coins the vague term ‘caliphism’ to signify a ‘subculture of different food and lifestyle, clothes and books’, supposedly leading us to ‘civil war’. Observing Asian shops and restaurants in the Birmingham area of Alum Rock, he laments that ‘there is not a Boots, Tesco, Sainsbury’s or Aldi to be seen’.

He is obsessed by appearances, proudly telling us that he is beardless because he wishes to remove ‘all outward signs that help to breed hypocrisy’. In Belfast, he notes praying men wearing socks. ‘This suggests they wear closed, Western shoes … thus telling me something about their cultural attitudes’ (no, me neither). When a man asks him to stop taking photos in a Glasgow mosque, Husain smears him as dressing ‘like a stereotypical Taliban member’.

Husain gets irritated that nearly every taxi he hires is driven by a Muslim, as though it is unfair that they dominate this low-paid, long-hours, lonely job (not everyone can work at the Tony Blair Faith Foundation). Other causes of social division – poverty, discrimination, racism – are all dismissed in favour of purely religious explanations.

Not that British Muslims don’t have issues. The lack of women in leadership roles in mosques and the inadequate facilities for them need urgent attention. But Husain’s hectoring tone won’t help. Faiza, one of the few women he interviews, texts before their meeting that she would rather not be greeted with a hug or a kiss. Husain shoots back that these outdated rules ‘were taken from the Jewish moral codes laid down in Ancient Egypt to prevent rape and keep women safe!’ While taking pot shots at the Muslim Council of Britain for its poor leadership during the 1990s, he fails to mention that it recently appointed a 29-year-old woman, Zara Mohammed, as its head.

For a writer who sees only bigotry in mosques, Husain is hardly a model of cultural sensitivity. A black man’s voice reminds him of Bob Marley. His disgusted account of a Shia religious procession in London belongs in a Hizb ut-Tahrir screed. Questionable statements by non-Muslims rarely get challenged. Two white men tell him there are ‘no-go areas in Blackburn’ and that the council ‘will threaten you with eviction if you fly the English flag’. Can this be true? Husain doesn’t investigate. When one woman tells him Muslims will ‘destroy our country’, he merely thanks her.

Although a scourge of ‘caliphism’, Husain is rather nostalgic for Islamic empires. The Ottomans and Mughals, he writes, ‘had their imams trained in the classical musical notes, but this is not the practice any more’. Their modern equivalents, the royal dictators of the UAE, are presented as a model: ‘While Muslims in Britain are fighting over demons and jinns, Emirati Muslims are launching successful trips to space.’ His suggestion that Muslims should pray for the Queen (some do, in fact) is tastelessly justified by saying that in Syria ‘the imams in mosques always prayed for President Assad’.

There are British Muslims who are now leading politicians, cricketers and actors (some even write novels). Husain ignores all this, as he does less recent developments, like the internet. He consistently fits unreliable ‘facts’ around a specious argument. On practically every page, Husain betrays the Enlightenment principles he so energetically thrusts on others. ‘We must not tolerate intolerance,’ he concludes. As Socrates advised, know thyself.