The little man with the big ideas was ahead of his time. Adrian Mourby celebrates his engineering legacy

When I was a student in Bristol, the Clifton Suspension Bridge was a place for romantic trysts and suicides. It looked as if it had always been there, a pair of stone pillars growing out of the cliffs of the Avon Gorge. It was the symbol of our radio station and everything else Bristolian.

But once upon a time there was no 700ft iron bridge spanning that gorge, just as there was no Temple Meads Station, no Brunel House and no SS Great Britain - just a smelly dock called Floating Harbour. Brunel built all four of these and he cleaned out the fifth by constructing sluices at Underfall Yard.

More than any other man, Isambard Kingdom Brunel transformed Bristol into the place we know today and yet he never lived there. More bizarre still, in his lifetime most of his grand Bristol projects were flops.

The SS Great Britain, despite being the wonder of the age, was sold off at a fifth of what it cost to build her, and ended up beached in the Falklands as a storage hulk. Brunel House, built originally as the Royal Great Western Hotel, was closed in 1855 when Brunel failed to get permission for a GWR terminus in the city centre, and the suspension bridge ran out of money. In 1852 all its chains were sold off to build the Royal Albert Bridge in Cornwall. When Brunel died, all there was to show for the first great engineering competition he ever won were two vast unfinished piers.

Today, when you see how Bristol is celebrating 200 years since the birth of the little man in the big hat, it is clear the city has forgiven him for his "overambitious" and "grandiose" plans.

In life, Isambard Kingdom Brunel was not always so popular in Bristol. His broad gauge railway had been forced to bow to Stephenson's standard gauge, and his vision of making Bristol the focal point of Britain's first package tours to America never got off the ground. But Brunel was eventually vindicated. Engineers now agree that the GWR's broad gauge was more stable and more capable of high speeds, and we came to see the advantages of Brunel's integrated tourism "package". Buying a ticket at Paddington which booked you through to Bristol, put you up overnight at the Royal Great Western and then loaded you on to the SS Great Britain for a 14-day journey to New York was a great idea, but ahead of its time.

The first rehabilitation of Brunel occurred soon after his death in 1859. By 1863 enough money had been raised locally to resume building, 11 years after the engineer had walked out with the words: "I am sick of it." The finished bridge was simpler than Brunel's original design, but its stark simplicity has aged well.

Quite why such a huge and costly structure was ever built is a bit of a mystery. The bridge connects leafy Clifton with rural Somerset. It was never going to increase trade or speed up 19th-century commuting times and, indeed, originally it wasn't even going to be wide enough for a horse and carriage. An eccentric local merchant, William Vick, bequeathed a considerable sum of money to fund a bridge across the gorge and all the 24-year-old Brunel did was to enter and win the ensuing design competition. If the bridge was a folly it certainly wasn't his.

The Royal Western Hotel fiasco was more Brunel's fault. In 1839, he and architect Richard Shackleton Pope opened the first railway hotel in the world - but without any railway. Brunel's GWR terminus should have fetched up on what is now College Green, above the docks. In the event the GWR ended up with a terminus on the other side of the docks at Temple Meads. Brunel designed it along mock-Tudor lines and it opened in 1841. It's still there today, housing the British Empire and Commonwealth Museum while Brunel's original train shed - at 72ft the largest single-span hammer-beam roof in the world - is now a car park.

Deprived of its railway station Brunel's "Gateway to the New World", as the Royal Western Hotel was known, closed in 1855. It had a brief subsequent career as a Victorian Turkish bath, but it wasn't until 1980 that its Ionic façade was rescued from decay to become the front of a new office block called Brunel House.

That Bristol never became Britain's premier departure point for America was not Brunel's fault. The city failed to expand its docks to cope with the increased size of ships and Liverpool soon superseded it.

As for "The Mammoth" itself, Brunel's Great Britain now sits in the very same dry dock where she was built and launched in 1843. The was the first sizeable iron ship to be driven by screw propeller and had an engine so powerful that drag was introduced on the propeller to slow the transmission down, lest it wore out too fast. Sadly, the ship was not well managed and it soon ran aground in Ireland, causing Brunel to write: "I was grieved to see this fine ship lying unprotected, deserted and abandoned by those who ought to know her value ... the finest ship in the world, in excellent condition, has been left and is lying like a useless saucepan kicking about on the most exposed shore that you can imagine."

Brought back to Bristol in 1970 as a hulk, the ship has been wonderfully restored and most decks can now be visited . You can even walk under the tray of water in which she sits and look up to see how the huge metal plates were riveted together, and inspect the gigantic propeller. Being designed by Brunel, it was, of course, the biggest there had ever been.

Isambard Kingdom Brunel was self-conscious about his lack of height. He was only 5ft tall, hence the big hats and big projects. Everything he did was bigger, more expensive or simply better than what everyone else did. When his two teams of miners met in the middle of the GWR tunnel at Box (the longest in Britain, of course) they were found to be only one and a quarter inches out. The man was a workaholic and died at 53.

There is a statue of him, hat and all, outside the old Bristol and West Building on Broad Quay. As memorials go it is pretty small, but then, so was he. Brunel's best memorial in Bristol is everywhere around you.