And it's so long, Frank Lloyd Wright: More than 30 years on, the Guggenheim Museum is again embroiled in controversy. Ultan Guilfoyle explains why

THE cartoon in the New Yorker caught the public mood. Two befurred Upper East Side women accosting a mounted policeman in front of a strange building: 'Say officer, are they allowed to do that on Fifth Avenue?'

The building was the Guggenheim Museum, perhaps the greatest work of one of the greatest architects of the 20th century, Frank Lloyd Wright, and the public reaction to its opening in 1959 was decidedly mixed. Quickly, however, the fun that New Yorkers poked at the building turned to affection and the building became one of the great New York landmarks.

Frank Lloyd Wright, after 17 years of relentless battles to construct the building, would have been proud. He never saw the finished product and perhaps it is just as well. He died six months before thebuilding opened, and in those six months several crude and functional alterations were made. Parts of the building were closed to the public to provide office and storage space for the museum director, James Johnson Sweeney, and his staff.

Thirty-three years after it was finished, the building remains the city's most controversial. A functional 10-storey extension has added to the lengthy debate over Wright's masterpiece.

The building was not, to begin with, an easy one in which to show pictures. Its key signature, the swirling, sweeping ramp, meant that it was impossible to look at a picture 'on the level'. None of this mattered to Wright. He did not care for the art that the building was to show; an astonishing collection of abstract 'non-objective' art. Indeed, he did not care much for art at all.

By the late 1980s the building had fallen into a sad state. Like many of Wright's buildings, it was not holding up well to the passing of the years. It looked and felt tatty. And the difficulties of presenting art in the building had, with the expansion of the Guggenheim collection, become even greater.

When Thomas Krens was appointed director of the Guggenheim in 1988 he decided to renovate Wright's building inside and out, to make it look like it had just left the original architect's drawing board.

Mr Krens had as his strong ally the architect Charles Gwathmey of the New York company Gwathmey Siegel. But Mr Gwathmey and Mr Krens had a battle on their hands. The very same people who so objected to the Guggenheim Museum back in the 1950s - those same befurred Upper East Side women from the cartoon - were now fighting to defend their 'masterpiece' from any interference.

Leading the campaign was the stuffy Carnegie Hill Neighbors Association, which represented the area of million- dollar residences immediately surrounding the Guggenheim. They hired lawyers, academics and architects to mount a campaign against Mr Gwathmey. They even managed to enlist the support of some of Wright's former associates and apprentices. Once their campaign gained momentum it seemed that they couldn't be stopped.

The affair was riddled with an irony that is not lost on Charlie Gwathmey. 'Some of the very same people, to a man and a woman, who were involved in a campaign against Frank Lloyd Wright's original scheme, now, 30 years later, have attacked my plans quite viciously,' he said.

Time and again Mr Gwathmey's designs were rejected by the New York City authorities, siding with the Carnegie Hill Neighbors. But each objection was met with stiff resistance from Mr Gwathmey, Mr Krens and the Guggenheim Foundation - and they finally won the battle. The extension opened at the end of June and has been a talking point ever since.

The results of the two-year renovation and extension - which cost dollars 55m (pounds 28m) - remain controversial but are regarded by many critics as an irrefutable triumph. The soaring beauty of Wright's original building seems all the greater now that you can walk right to the top of the quarter-mile ramp.

Gwathmey Siegel's slender new wing, with its three double-height galleries, almost doubles the space available for the Guggenheim collection.

(Photograph omitted)