Banner In THE WEST By John MacLeod (Birlinn at £25)

THE reason why Wee Frees disapprove of sex conducted in the standing position, it has been said, is because it may lead to dancing. And so it is reassuring to learn that a much-loved 19th-century Highland evangelist called John MacDonald not only approved of dancing but insisted on accompanying the black art on his pipes. Indeed his friend, one Evander MacIver, was moved to comment: "I used to see as merry dancing in Dr MacDonald's house as anywhere, when many folks thought it was a sin to dance."

We have John MacLeod to thank for running this vile calumny on the character of the Free Church of Scotland to ground in his brilliant new book, Banner In The West: A Spiritual History Of Lewis And Harris. MacLeod knows all about the casual discrimination and wilful misunderstanding suffered by his co-adherents of the Free Kirk. He has personally endured it throughout a colourful career as writer, historian, broadcaster and journalist. For those who love the beauty and splendour of written English, his newspaper columns in The Herald and, latterly, the Daily Mail, are items to cherish. Yet in the sometimes complacent Lowland media community, MacLeod is viewed as an uncomfortable anachronism. Why does someone who writes with such poetic ease on national and global politics, and on the pools and eddies of the current economic whirlwind, who can invest feeding time with the chooks on his croft with emotion, wit and import, continue to abide on Lewis?

In the west of Scotland's café society and journalist hubs, MacLeod is often dismissed as an oddity for public devotion to his beloved Free Church of Scotland. His insistence on refusing lucrative commissions which would entail him working on the Sabbath have marked him out as a fool. A deeply controversial piece about the murder of the Soham children in 2004 led to his departure from The Herald Kevin McKenna was duty editor at this time.

Banner In The West is a book John MacLeod was born to write. It tells the story of how the rich and vibrant character of Evangelical Protestantism in Lewis and Harris (what MacLeod fondly refers to as The Long Island) came to hold sway. It chronicles the birth of Christianity in Scotland and how, in the Western Isles, it became the no-nonsense and absolute faith in the saving power of Jesus Christ that the rest of the world mocks and derides for its seeming intransigence and bigotry.

Yet this is no mere arid chronicle of an outdated belief structure, for to look at the tumultuous progress of Christianity in the Western Isles is to look into the very soul of Scotland and its story. At the very outset MacLeod describes these islanders' dread of superficiality in religion. It is no wonder. Even in spiritual affairs, he states, "the doings of men are shaped by soil, climate and topography".

What follows is a work of astonishing but vivid research into the lives and influences of an assortment of unsung, but very Scottish heroes who suffered to bring an unsentimental and living faith to their lands. They had to contend with the worldly and often baleful influence of Rome, the complacent curse of religious moderation and the neglect of a Lowland-based Church of Scotland unwilling to commit men and resources to one of the most inhospitable terrains in Europe - certainly not for these intense wee collectives of remorseless Highlanders who would brook no compromise over the Biblical and sovereign word of God.

And although this is primarily a historical narrative, MacLeod cannot resist letting some of his Highland prejudices out for a gambol. His work is all the better for them, as there are few who escape his nimble excoriations here. Rome gets it in the neck for an assortment of errors. According to MacLeod, it's not that Catholicism doesn't preach the Gospel of Christ crucified, it's just that it comes with spurious and man-made junk, much of it purely as a result of bitter and byzantine Vatican politics rooted in the Middle Ages. Memorably, the Iona Community doesn't escape his wrath; MacLeod dismisses it as "the Liberal Democrats at prayer".

The charm of Banner In The West is contained in the mining of locally sourced material. This has provided a pot-pourri of anecdotes based around the heroism of a small group of Scots Christians. MacLeod's storytelling gifts show us how the sacrifices made by this legion of the brave have given us a peculiar Christian reformed faith hewn from the very experiences that make us all Scots. He shows us how evangelical religion brought literacy and aspiration to the benighted Highlands and Islands, and how it inspired disciplined political action against oppression. In time, this early brand of Christian populism would inform modern democratic ideals across the world.

When Jack McConnell was first minister, he somehow thought it was a good idea to go round the world marketing Scotland as a small country and describing sectarianism as its "secret shame". Like many other New Labour mantras, there was more sophistry than source. Under McConnell's Cabinet, we became the most politically correct nation on Earth. Even the Catholic Church got in on the act last month when it saw fit to warn football fans about the evils of the hokey cokey (supposedly a mocking of the Latin mass). Yet the most unedifying incidences of sectarianism might well be suffered by those whom we choose to label, in glib discrimination, as "the Wee Frees".

In this respect, MacLeod's book is timely. The dawn of Holyrood, with its attendant political commentators and acolytes, has launched a thousand dreary treatises on the meaning of Scotland and what it means to be Scottish. Where does our destiny lie? How significant are we? We have become a nation of navel-gazers. Disturbingly, it is clothed in a vacuous, humanist view of the world that seeks constantly to airbrush Scotland's vivid and Christian heritage from our island's story. The Catholic Church, arguably lacking leadership since the death of Thomas Winning, is bereft of unity among its hierarchy and no longer speaks with the moral authority it once had.

The Church of Scotland's beliefs seem tailored to fit any prevailing populist agenda. Meanwhile, the Episcopals will not soon recover from the devastation wreaked by Bishop Richard Holloway, the world's first atheist Christian prelate. Perhaps that is why it is really only the Free Church - gloriously Scottish and thrawn, never caring for the changing opinions of others and hanging on grimly to its deposit of faith - that attracts such opprobrium from us Lowland sophisticates.

The Free Church should be proud of John MacLeod, faithful chronicler and standard bearer of a scorned faith.