A man of iron - on the sea, above ground and below

What are taken to be the great days of British engineering have a clear chronological and geographical focus: the booming industrial cities of the north of England in the Industrial Revolution. And rightly so because, as Britain industrialised, its industries moved north: textiles from Bradford-upon-Avon to Bradford in Yorkshire, shipbuilding from the Thames to the Tyne. Trade followed, shifting from Bristol to Liverpool.

Indeed, the engineers most highly honoured in the 19th century were the Scot James Watt and the Tynesider George Stephenson. By the late 20th century, as Christine McLeod shows in a central contribution to this collection, Isambard Kingdom Brunel (1806-59) had become the iconic British engineer, and his association with Bristol, not Manchester or Leeds or Glasgow, has become central to that.

If we compare the histories told of British engineers up to a decade or so ago with recent accounts, another striking change becomes apparent. Until then, an account of the heroic age of the early 19th century was just the prelude to a story focusing on the unremitting subsequent decline in the status of British engineers. Stressed were their division into competing institutions, their poor academic education, their low numbers and how, from 1850 - or was it 1870? - foreigners did it so much better. The industrial North, went the argument, came under the thumb of the financial, aristocratic and anti-technological South.

Not any more. This declinist account seems to have died around 1997: since then the spin machine has accentuated the positive. Jeremy Clarkson, the celebrated boy-racer, was able to convince viewers of TV's Great Britons contest to place Brunel second only to Winston Churchill in this electronic pantheon.

This celebratory volume produced by the Bristol Cultural Development Partnership does not make sufficiently clear that Brunel does not fit the standard image of the British engineer, which is not to say that he was atypical. Far from being from the labouring classes, he was the son of a famous engineer, Sir Marc Brunel. The father has remained rather obscured by his son's even greater achievements, but he is rescued here in an essay by Andrew Nahum. Sir Marc, as well as being a French royalist, was associated with great engineering works in London and the (southern) naval dockyards: the Thames Tunnel (not completed until 1843, and now used for the London Underground) and the Portsmouth block-making machinery that made the wooden pulley-blocks needed in huge numbers by a sailing navy. His son Isambard spent his early years in Portsmouth, London and France. He learnt engineering mostly from his father, for whom he worked, notably on the Thames Tunnel.

His base was London, in Westminster, home of the great consulting engineers who were members of the Institution of Civil Engineers, then as now only yards from Parliament. His staff, for he was an employer, worked with him in London, although some were in the field. Civil engineering was then elite engineering of all types, not merely a particular branch of engineering. For all his association with Bristol, Brunel was in no sense a West Country engineer.

Yet the link is of particular interest given that Bristol, while one of the great cities of 18th-century England, was declining relatively in the 19th century. The slave trade was gone, and the tidal River Avon was too small at Bristol to deal with ships of increasing size, most notably Brunel's own. Bristol had no Manchester in its hinterlands.

Young Isambard's first major solo project resulted from his winning a competition, with his father's help, to build a bridge across the Avon in Bristol. That was in 1831; but work on the bridge, which was to become famous only much later, did not start until 1837 and stopped in 1843, not to start again for 20 years. His first construction work in Bristol was the improvement of the floating harbour system. Angus Buchanan, one of the two biographers of Brunel represented in this collection (the other is Adrian Vaughan), makes this very clear with a fascinating account of this work and its long legacy. The floating harbour was a major piece of Enlightenment engineering, which gave Bristol a large harbour in which ships were permanently afloat. Previously, they were left high and dry as the tide receded, for even as high upriver as Bristol the Avon was very tidal. Brunel was to build two important ships in shipyards within the floating harbour, the Great Western (1837) and the Great Britain (1843). The latter could hardly leave it, and neither sailed from it again. At the end of the 20th century, the floating harbour would once again become central to the Brunel story.

The story of Brunel can also be told as a story of tragedy and decline. He died young, and many of his creations were one-offs rather than beginnings of new things. The Bristol connection helped him become the chief engineer of the Bristol Railway, which became the Great Western Railway, whose first aim was to link Bristol to London. Construction started at the London end in 1836. The line was built to carry passengers at speed, rather than being modelled on the goods-carrying thinking of the earlier railways. To achieve his aims, Brunel gave the railway a very broad gauge (the distance between the rails). Yet to allow interconnection with the rest of the system, the GWR soon had to be both broad and standard gauge, and by the 20th century was standard gauge only.

The Great Britain , the greatest ship of its time and a pioneering steamship, was reduced to a sailing vessel, and the Great Eastern , the greatest leviathan of them all, ended up giving out submarine telegraph cables rather than carrying passengers in luxury. But as Andrew Lambert interestingly has it, the Great Britain in particular not only pioneered a new class of ship as a steam-powered, propeller-driven Atlantic liner but went on to pioneer steam-assisted passages to Australia and then became a pioneering sailing clipper of the late 19th-century sort.

Key to the development of the reputation of Brunel has been the survival of Bristol-related material. The Great Britain ended up in the Falkland Islands, and in the 1960s a campaign launched in Bristol got under way to bring it back to Bristol, where it arrived in 1970, in the very dock in the floating harbour where it was built. The whole floating harbour was then derelict, and the city was much less keen on its heritage than it was to become. I remember it well. I went to school in central Bristol, next to the main part of the floating harbour, and reached it by a bus route that took me along the mysteriously named Feeder Road, which paralleled the Feeder Canal (which kept the floating harbour floating) and then went alongside what seemed to be the River Avon, but was the New Cut, which took the tidal waters and the downstream flow that had once gone through what was now the harbour. The route crossed the New Cut twice, close to Brunel's Temple Meads railway station, then crossed the floating harbour again, before reaching its destination close to another part of the harbour. But this relic of Bristol's past was hardly understood, and for many years Bristol did not appreciate the potential of having the Great Britain .

The fact that Bristol docks remained in marginal use was central to its survival and to the fact that it was possible to get the Great Britain there at all. Now, the completely renovated Great Britain is a key display in an extraordinarily rejuvenated and huge leisure area teeming with boats, museums and banks. This is the heritage industry, engineering branch. The famous ship in its original dock is in just the right place, the centre of a booming post-industrial city. One does not have to go very far to get a spectacular view of the Clifton Suspension Bridge. The bridge, like the ship, has rarity value. It is one of the very few remaining suspension bridges from the 19th century and, even more than the ship, benefits from a stunning location, as estate agents might say. Brunel's own Hungerford Bridge, which he actually completed and which was of similar scale, did not survive, though its chains were used to build the Clifton Bridge after Brunel's death. Had it survived, it would not have made the impression that spanning the Clifton Gorge did.

Images matter as much as location. Photography in particular has played a part in Brunel's late success. This book, which is lavishly illustrated with more than 400 images, many in colour, contains a photograph of the Hungerford Bridge by Henry Fox Talbot himself. One cannot resist the footnote that the GWR went through Fox Talbot's estate at Lacock Abbey in Wiltshire, which is now itself a museum. There are also photographs of the unfinished Clifton Bridge in the 1850s, and the iconic ones of Brunel with the Great Eastern still stuck on the shores of the Thames, where it was built.

Image and location help give us this book, the product of a huge Bristol-centred PR effort around the bicentenary of Brunel's birth, funded in part by the National Lottery. Unlike many such productions, this book, despite the silly title, and one or two essays one could have done without, does have the merit of bringing the work of the relevant academic experts to a wider public. And, in reflecting on the celebrity of the engineer and how it has changed over time, it invites us to reflect on the fickleness of reputation and to think more about the engineers whom the Victorians esteemed higher than Brunel. At the same time, it reminds us that engineers did much more than work in industry; that trains, ships, docks, locks, tunnels and bridges were and remain important, even in what is misleadingly claimed to be the "information age". And it is worth recalling that British engineering was never all northern, and that Bristol and London, Portsmouth and Plymouth have a history of technology, too.

David Edgerton is professor of the history of science and technology, Imperial College London.