Across the Sunni world, growing fear of Shia influence exposes the cultural schism that exists between the two traditions

Six Shia Muslims have gone on trial in Jordan, accused of "promoting Shia ideology and instigating religious sectarianism". Their case – the first of its kind in Jordan – is being heard behind closed doors in a military court.

Jordan is a Sunni-majority country but has no law that prevents Shias from practising their faith and its constitution says very clearly that there shall be no discrimination "on grounds of race, language or religion".

There is no suggestion that the accused did anything more than a bit of missionary work – holding meetings, issuing membership cards and raising funds – but the case reflects a growing fear of Shia Islam among the Middle East's Sunni regimes.

In Egypt last June, Hassan Shehata, a Shia cleric, was reportedly arrested with dozens of his followers and 13 were said to have been detained on charges of spreading Shiism.

Egypt has had a small Shia community for centuries, though today it's probably less than 1% of the population. The sect is not officially recognised and the Egyptian Initiative for Personal Rights has documented periods of harassment by the authorities – arrests, interrogation, torture, etc – dating back to 1988.

The Sunni Arab regimes, most of which use religious credentials to bolster their claims to legitimacy, have become increasingly apprehensive during the last few years – mainly as a result of the Iraq war, which brought Shia Muslims to power in Baghdad, to rule alongside those already in place in Tehran.

From time to time there are also outbreaks of scaremongering in the media, very similar in tone to the western newspapers articles that claim Muslims are taking over Europe. One Egyptian magazine warned of "a real danger that Egypt and other Sunni countries might be converted to Shiism".

Shia Muslims in Sunni countries tend to be viewed as fifth-columnists with uncertain national loyalties. Shehata's arrest seems to have been prompted by two visits he made to Iran, though it also coincided with the capture of an alleged Hezbollah spy ring.

Shia Islam – which accounts for no more than 15% of all Muslims worldwide – has certainly been making a few converts among Sunnis. A Saudi Shia told me yesterday that he personally knew of half a dozen Jordanians who had converted. More widely, though, recent events have aroused curiosity about Shiism among Sunnis and, in some cases, admiration. Iran's uncompromising stance over its nuclear programme is contrasted favourably with the ineffectual peformance of Sunni Arab regimes. Similarly, Hezbollah's defiance of Israel in the 2006 Lebanon war.

But there's more to it than politics, as an article in Al-Ahram Weekly explains:

For Nabil Abdel-Fattah, who edits the State of Religion in Egypt annual report for the Al-Ahram Centre for Political and Strategic Studies, Shia jurisprudence is dynamic, flexible and pragmatic – which makes it attractive to many a Sunni frustrated with lack of change: 'For many years Sunnis refrained from ijtihad [independent thought] and tended to adopt a hardline approach similar to the Saudi Wahhabi model.' For Sunnis this tendency, Abdel-Fattah elaborates, has led to a gap separating daily life from religious provisions, driving Sunnis to embrace Shiism.

Other factors include the erosion of spirituality from Sunni life, with no provision for anything comparable to the Passion of Christ, to which Egyptians arguably relate. [In contrast to Sunni – and especially Wahhabi – puritanism, many Shia practices are much more akin to Spanish or Italian Catholicism.]

Less obviously, the fact that millions of Egyptians have worked in the Gulf countries since the 1970s makes the population more open to different schools of thought.

Shia Islam's links with Iran (and, by implication, with the Iranian regime) have parallels in Judaism's association with Israel and Israeli government policies. As in debates about antisemitism, the line between politics and prejudice easily becomes confused.

Regardless of what the Iranian government does, though, Shia Muslims in Sunni countries have every right to practise their faith and, if they wish, to try to convert others.