The American architect given the task of designing Birmingham's tallest building has spoken of his vision for a sleek 50-storey tower that would rival New York's Rockefeller Centre as a civic and cultural asset.

Upbeat comments from Eric Kuhne, who yesterday met city council leader Mike Whitby to discuss plans for the skyscraper, raised hopes that the #500 million Arena Central development (artist's impression pictured) will finally get under way after a seven-year delay.

Mr Kuhne's visit coincided with a warning from an urban design expert that lack of imagination and an unwillingness to take risks was stifling the development of cities such as Birmingham.

Charles Landry urged planners to adopt "360 degree thinking" and not be too concerned about being told that innovative schemes might not work.

Mr Landry, a best-selling author of books on city development, runs the Comedia planning consultancy.

Addressing the Urban Land Institute Europe Cinderella Cities conference in Birmingham yesterday, Mr Landry said the risk agenda was neutralising potential for exciting regeneration.

He added: "Everything is organised on a risk-based agenda. Everything has to be based on evidence. It is a British problem. A lack of imagination."

He urged developers and planners to think "at the edge of your competence".

Mr Landry added: "Birmingham needs 50,000 acts of vivid imagination to transform itself. The edginess you need to push at the boundaries is precisely the sort of thing that is uncomfortable."

* What do you think of plans for a New York-style skyscrapers in Birmingham? Click here to get in touch *

Mr Kuhne, who was also at the ULI conference, held at the Colmore Row offices of Wragge & Co, said he believed the Arena Central tower would quickly become one of the Midlands' most talked about buildings.

First proposed in 1999, Arena Central was originally to have been the tallest building in Britain.

But the latest thinking, for a 150-metre structure, means that although it will outstrip anything else in Birmingham, it will still be almost dwarfed by far taller towers in London.

There are also outstanding issues to be resolved over concerns raised by the Civil Aviation Authority about Arena Central's position on the flightpath to Birmingham International Airport.

Miller Developments and its partner Bridgehouse Capital, the investment company run by Midland millionaire Andy Ruhan, were recently joined by property firm Dandra and expect to begin work on the first phase of Arena Central this summer.

Mr Kuhne, who is the managing director of London-based CivicArts and an internationally-acclaimed architect, was appointed to design the tower.