James Gandon was the architect who transformed Dublin, but his life is rarely celebrated. Gerry O'Donovan admires a superb new documentary.

On the night of 26th April 1781, a gout-ridden, middle-aged Englishman boarded a packet boat in Liverpool, bound for Dublin. His arrival was shrouded in secrecy, and he was immediately spirited away to the home of one of the country's most powerful men - Rt Hon John Beresford, chief collector of taxes. There he was kept in virtual seclusion to ensure no one discovered the purpose of his visit as, almost certainly, it would have provoked riots.

Who was this threat to Dublin's civic order: a spy, a political agitator, a fugitive from justice? In fact, he was an obscure London architect, James Gandon, commissioned to design and build a new Custom House for Dublin - the biggest, most controversial building project of the day.

Nowadays Gandon's name is familiar to anyone who has ever taken the time to marvel at Dublin's finest buildings. Not only did he build the Custom House but also the Four Courts, The Kings Inns, and the great portico entrance to the old houses of parliament on College Green. Over twenty years he spearheaded the transformation of Dublin from shabby provincial city into one of Europe's great capitals. No other architect has had greater influence on Dublin, and yet little is generally known about him.

Look around Dublin's bookshops and libraries, the shelves are crammed with biographies of the country's great writers and artists. But what of its greatest architect? There are glossy coffee - table books and tourist pamphlets celebrating his work. But his life? If your lucky you might find a copy of his memoirs, published by his son in 1846, but now long out of print. Other than that you would be hard pressed to discover anything other than a brief résumé stuck in the back of an architectural tome, an appendix here, a footnote there.

However James Gandon - A Life, redresses the balance. Sé Merry Doyle's documentary is an absorbing account of one of the neglected heroes of Irish culture. And long overdue. After all, it is not as if Gandon was a drudge whose life would be of no interest to anyone other than architects keen to study his extensions, elevations and engineering techniques. On the contrary, his life and, especially, the time in which he live are fascinating. He was loved and reviled in equal measure by the Irish. Dubbed as the "architect generalissimo", he was accused of building vainglorious monuments to himself and was frequently the subject of scurrilous attacks in the press, described in one as: "a Machiavel, a depraved sensualist who consorts with the most scandalous women in Dublin, and a secret visitor to brothels".

So who was this man and why was he bought to Dublin? According to Sé Merry Doyle, Gandon was one of the most fortunate souls who blessed with great talent was exactly the right place at the right time - and made the most of it. Gandon had greatness thrust upon him and his story makes exceptionally good television.

Having hooked you as neatly as a thriller with Gandons cloak and dagger arrival in Dublin, Doyle tracks back in time to his beginnings in London. We discover a man of relatively humble origins (the son of an eccentric Huguenot alchemist who had "more of a talent for turning gold into base metal"), whose precocious drawing skills won him an apprenticeship to the celebrated architect William Chambers, and an introduction to London's fashionable artistic circles. At the salons of his friend Paul Sandby, he first met Lord Carlow, an Anglo - Irish aristocrat with a refined taste in the arts and a consummate desire to bring some of the best back to Ireland.

Carlow suggested Gandon to John Beresford as the new architect for the new Custom House and thus, to quote Doyle "catapulted him to fame as Ireland's finest architectŠ and plunged him into the heart of a British colony on the brink of rebellion".

Gandon arrive in Ireland during a period of enormous political turmoil. The British Government had just been forced by Henry Grattan's volunteer army to grant independence to the Dublin parliament. A small cadre of Anglo - Irish aristocrats and protestant powerbrokers believed that Ireland's claim to nationhood depended on cultural achievement as well as economic prosperity. They were determined to transform Dublin from a cesspit of stinking alleyways and slums into a city worthy of being called a national capital. To do so they needed an architect capable of designing building of international repute and Gandon, a prime exponent of the newly fashionable neoclassical style, was chosen for the job.

Gratin's parliament was a Protestant, landed, ascendancy power that had nothing to do with Ireland's simmering mass of dispossessed Catholics. Its refusal to share with the Catholic majority eventually precipitated the 1798 rebellion, which brought the whole grand edifice down and resulted in the catastrophic Act of Union in 1802.

The focus of power and money then shifted to London, and Gandon's career fizzled out. But the crucial point, suggests Doyle, is that for those twenty turbulent years, Ireland was in the hands of a powerful group of Protestant politicians whose enormous wealth allowed them to indulge their dreams of transforming Dublin.

On this premise Doyle builds a superb documentary which not only glories in Gandon's exquisite architectural achievements, but offers a fascinating picture of life in the late 18th-century Ireland. Among the numerous experts unravelling the tale are the historians Maurice Craig and Edward McParland, and the architects Hugo Duffy and Sam Stephenson.

Charles Haughey the former Taoseach was persuaded to open up Abbeville, his magnificent Gandon-designed home to the cameras. And in a nice touch the actor Christopher Casson reads from Gandon's memoirs, putting flesh on the bones of this man whose memory is so undeservedly neglected.

To complete the picture, Doyle follows Gandon's buildings down through history to the present day, bemoaning the enormous damage done by fire to both the Custom House and the Four Courts during the war of independence.

By way of heartening postscript, however, he tells the story of Emo Court, the residence Gandon built for Lord Portarlington in Co Laois, which after years of dilapidation and neglect was lovingly restored by its owner and recently donated to the nation - gratefully received by President Mary Robinson. Without doubt, this is the best documentary you will see on television for a long time.