The island faiths have always seemed to me, at distant consideration, a fairly detached bunch, roused only by the threat of Sunday ferry sailings or the sight of an untethered child’s swing on the Sabbath. Okay, they don’t like anything much unless it involves walking slowly to church in a hat formerly owned by their great-grandfather, but these austere elaborations of the Calvinist reform tradition — the Free Church, the Free Church (Continuing) and the Free Presbyterian Church — always seemed too remote, too isolationist, to care about the world beyond Benbecula.

But there’s one thing that does rouse their Presbyterian passions. They’ve really got it in for the sons of St Peter. They are implacably set against Catholicism. One might imagine that the recent influx of Polish people of that persuasion might seem something of a cross for them to bear, were they in the business of bearing crosses, that is.

In fact, the Poles are catnip to the Protestant proselytiser. They’re still — it is assumed — tentative in their adopted nation, vulnerable, looking for hospitality and succour, removed from the wellsprings of their faith. The Rev John MacLeod, assembly clerk of the Free Church (Continuing), says they are a natural constituency.

“While we have no formal strategy to target the Poles, it would be exceedingly strange if we were not looking to evangelise among that community. We do most of our missionary work in Scotland in Inverness, which is chock-a-block with Poles. It’s becoming a natural constituency for us. They have little to go home to when they come off shift. They have social and spiritual needs that are not being met.”

It’s a curious idea that a sentimental Slav might cheer himself up with a few chapters of Martin Luther but, heigh ho, horses for courses. And it’s marginally more likely than any native Scottish or Irish immigrant Catholic embracing the island faith. What’s more, the signs are that Scotland’s Poles are returning home. To an evangelising faith such as the Free Church (Continuing), this fact is rather like firing a starting pistol. The race is on to claim the Poles for Calvin, so that they might take the good word back to Warsaw.

The Rev James Gracie, a minister with the Free Church (Continuing), is determined not to miss an opportunity. He is one of a number of extreme Presbyterians targeting the Polish community.

“My experience of bringing the Gospel to Roman Catholics is that they’re easier to speak to than hardened Protestants. At least Catholics can associate with a spirituality and often they’re looking for something. Protestants look for nothing. They’re already saved, they think. The sense I have is that the Poles have a softer aspect to them; they have the innate respect for the collar and spiritual matters. You can approach and speak to them easily.”

“What you must remember about Polish Catholicism,” says Jeff McDonald, a Church of Scotland elder at Glasgow Cathedral, “is that it’s very conservative, very right-wing. It dovetails quite neatly in that respect with the more marginal forms of Presbyterianism. In the 1600s, Polish Calvinists had the majority in parliament. Poland was very nearly a Protestant nation. The thing that those communities respond to in Scottish Presbyterianism, I’m told, is its concern for the souls of worshippers.”

It does not stop with the Poles, he says. “There are about 50,000 Lutherans in Lithuania, whose emigres also head for the Highlands and islands and have also become a focus for Presbyterianism. It’s becoming a fertile area for evangelical work.”

Partick in Glasgow has proven itself a magnet for both the Hebridean and Polish diasporas. A forthcoming episode of Taggart involving skullduggery among Glasgow’s Polish expats was filmed recently in Hyndland Street; nearby is Polish Taste, a delicatessen. Until recently the noticeboard here carried a leaflet advertising a talk in the local Free Church (Continuing) entitled Reaching the Catholic with the Lord’s Love. It was on display only briefly, no doubt until its slights against the Mother Church dawned incontrovertibly.

The talk is delivered by one Richard P Bennett, of Del Valle, Texas. A former Dominican priest, he’s on a seven-date tour of Scottish Presbyterian churches: Edinburgh, Aberdeen and Glasgow this week, the inner and outer Hebrides next.

Bennett has specialised in ministering to the Eastern bloc. The website of his organisation, Berean Beacon, is translated into Polish, as is his pamphlet From Tradition to Truth. Also available are copies of From Polish Catholicism to Trusting Christ Alone, the testimony of one Peter Slomski, raised in Halifax by Polish emigre parents and a fellow convert to biblical Christianity.

For those accustomed to the spiritual kindergarten that is the Church of Scotland, a Free Church (Continuing) service is formidable, perhaps even a little scary. The psalms are led by the Presenter, a man at the front who wails in a curious keening voice until the psalm gets to a catchy bit and everyone else joins in. The pews are filled by people with long, anxious Alastair Sim faces. The mournful sound almost makes you smell the seaweed on the beaches of the Minch.

Bennett’s rhetoric is little changed from the Lanarkshire Presbyterian James Begg’s 1852 Handbook of Popery. Catholicism is “utterly obnoxious”, “horrendously evil” and “quite simply, the Occult”. What’s more, he adds, though perhaps rather tangentially, retired nuns “are often very lonely women who live very miserably in cubicles in nun retirement homes”. There’s a tarantula on the communion wafer here, of course: did none of this occur to Bennett during his eight years of Dominican training and his three decades as a priest? Apparently not; but then he had a car accident and while convalescing really had time to think about it, apparently.

I ask him why he thinks the scratchy rigours of Presbyterianism might appeal to the Poles. “Because the more devout a city, the greater its immorality,” he says. “You only have to go to Warsaw, as I have, to see that. In Poland, the Catholic heritage means the inhabitants have become hardened to immorality. They’re seeking relief from it. So our job is to give them the reformed church as a kind of gift.”

Whether it’s a welcome gift is another matter: “I think not, says Father Wojcoech Kwiatkowski, Polish priest at nearby St Peter’s in Partick, which celebrates at least one mass in Polish each Sunday. “For Poles, Catholicism isn’t just a religious or spiritual matter,” he says. “It’s also about our culture and history. Our Catholicism articulates our patriotism. Polish emigrants can neglect their faith, certainly, but it always comes back.

“Poles come to Scotland for work. They work very hard, often on Sundays, because they go into the service industries. There can be a pull towards Protestantism, but it always proves temporary.”

Piotr Leszczynski, vice-consul general at the Polish consulate in Edinburgh, believes his countrymen would view Presbyterianism as odd: “Something like 98% of us are Catholic. They would have nothing against the Scottish Protestants, but it’s a faith that has virtually no presence in Poland now.”

As is the Catholic attendance at Bennett’s address: there are maybe three of the faith here among the audience of 80 or so, but they disappear before tea and biscuits. I recall the words of Bart Simpson when he calamitously switched faiths: “Why focus on the stupid little things that divide us when we can concentrate on the stupid big things that unite us?” Amen to that.