Architecture: A bridge too far-sighted to be built: Richard La Trobe Bateman has engineering in his blood. But his elegant design, which would have spanned Bristol's docks, was pipped at the post by another. Peter Dormer reports

Richard La Trobe Bateman is a designer and maker of bridges. His designs are like no others and his blossoming talent is much admired by many of Britain's leading engineers.

British bridge design is currently the subject of much high-level discussion. The Department of Transport has rightly been accused of being unadventurous in its choice of structure for the massive new East London River Crossing, and the Royal Fine Art Commission has published a booklet on the subject calling for more adventurous design. At such a time, Bateman's experiments are a clear pointer to what bridge design could become if only we wanted it to. But his latest highly inventive project - an elegant 52m pedestrian and cycle bridge spanning St Augustine's Reach in the heart of Bristol Docks, designed to open in the middle to let boats pass through - has been rejected in favour of a less inventive design. This is sad, because Bateman's bridge is as original as it is desirable.

Along with several other designers and artists, Bateman had been asked by a committee formed by the Arnolfini contemporary arts gallery, Bristol, to submit proposals for a bridge to cross St Augustine's Reach to the gallery. He was pipped at the post by a sculptor called Eilis O'Connell.

As with most commissions carried out under the 'art in public places' banner there was no public consultation at the time, which is a shame, because the people of Bristol - home of Isambard Kingdom Brunel's magnificent suspension bridge across the Avon Gorge at Clifton - will get a nice bridge, but not a truly imaginative piece of forward-looking engineering. Bateman's enthusiasm for the subject, however, remains irrepressible.

At home in his Somerset workshop he bobs up and down in sheer excitement at the wonder of physics and the pleasure of making structures that, while thrilling to look at, refuse to fall down. Bateman is how you would imagine a Victorian clergyman to be, or at least one who has just read Darwin and renounced religion in favour of modern science.

'A bridge,' he says, 'is interesting because you can make your structural points so clearly. There is a real joy to be had in demystifying structure, and I am trying to devise rigid structures which use the minimum amount of material and which are the least trouble to make.'

A working model of the Bristol bridge cannot fail to intrigue. The two halves of the span swing upwards and sideways from one another. The effect is like watching the way the muscles in your forearm pull round when you twist your wrist. Bateman's bridge is a clear demonstration of what artists mean when they talk of 'articulating space'.

The supporting structure consists of two rigid compression members and two tension cables, creating a simple but highly dramatic 'tent'. The bridge itself is suspended from the apex of the 'tent'. The two halves are drawn apart by two motors, one on each side. Bateman has avoided massive piers and hydraulic rams and replaced heavy-duty engineering with a lightness of touch.

The Batemans live in picturesque austerity in a pretty Somerset village. Their stone house is furnished with Bateman's work and it has been intelligently and subtly refurbished by his wife, Mary, an interior designer.

Superficially, the Batemans might appear 'crafty'. In his adjoining workshop he makes chairs, and small bridges to cross rural streams. She styles interiors and bakes bread.

Yet the Batemans are not open- toed sandal wearers or members of the English Guild of Craft Whimsicalists. Instead, they are rare examples of an endangered breed: non- institutionalised professionals, living an intellectually and artistically fulfilling life on little money and away from the frantic socialising of the art world.

Engineering is in Bateman's blood. His great-great-great-great- grandfather worked with Robert Stephenson, the Victorian engineering genius. Bateman's ancestor assisted Stephenson on the magnificent Britannia Bridge, which crosses the Menai Strait between Anglesey and the Welsh mainland. Succeeding generations of Batemans built drains, dams and churches.

Richard La Trobe Bateman intended to train as a naval architect but ended up in the late Fifties at St Martin's School of Art in London, studying sculpture under Anthony Caro. Caro, now knighted and acknowledged as one of the world's best abstract sculptors, was not, like Bateman, an engineer manque. Bateman might have caused Caro some puzzlement since St Martin's was ostentatiously avant-garde, and there was young Bateman working away on the human figure using a plumb line, callipers and the rest of the paraphernalia and procedures of traditional modelling.

Bateman was not, however, interested in anatomy or in producing academic sculptures. He was exploring the underlying structural principles of the body. The human figure was of interest because it appeared to be engineering on the hoof. It was a part of Bateman's broad interest in design, an interest that most Modernist sculptors then and now violently repudiate.

After St Martin's, Bateman studied furniture design at the Royal College of Art. He argues that to pare down a design for a chair to a minimum of material and constructional complexity is more difficult than doing the same for a bridge.

'The load that a bridge has to carry is light compared with the weight of the bridge itself. A bridge's main task is to support itself, and withstand winds, whereas a chair is very light compared to the load it must carry.'

But Bateman's bridge will have to find a new home. The winning design for Bristol is the result of a collaboration between the sculptor Eilis O'Connell and the consulting engineers Ove Arup and Partners. Their design features two large supports in the centre of the dock, and a central span that opens like a single-leaf drawbridge. Powered by hydraulics, the lifting span is hinged with the aid of two massive counterweights designed by the artist in the form of large cones or trumpets. They are a clear extension of O'Connell's sculptural work, a little of which is displayed at the Arnolfini in a small exhibition about her bridge.

These days there is pressure to involve artists in minor public works of the kind represented by the St Augustine's Reach commission. Yet arguably, without the intellectual flexibility of broader training in design and engineering, most artists can contribute only an enlarged version of their studio work.

O'Connell's studio work is certainly gracious and engaging and no one doubts that Ove Arup and Partners can make almost any structure stand. But perhaps in future, talented sculptors will be commissioned to design sculptures, while bridge designers will make bridges.

A boat from St Augustine's Reach will take you within the hour beneath Brunel's Clifton Suspension Bridge. Originally there were plans, subsequently dropped, to decorate the bridge with Egyptian- style sculptures.

Had Brunel been building in the Avon Gorge today, would he have been forced into a 'meaningful' collaboration with a contemporary artist? Sadly, yes, and we might have been poorer for the decoration being richer.

(Photograph omitted)