Leading architects fear the multi-million plans to revamp the historic heart of Winchester could spoil the cathedral city.

Winchester-based Robert Adam and Huw Thomas are worried about the possible massive scale of the £100m Broadway-Friarsgate scheme. They fear seven-storey tower blocks could dominate the skyline, competing with the cathedral in height.

Mr Adam said: "If we have buildings of this bulk and height, it will utterly change the character of Winchester." He said project architects, Allies and Morrison, were known for their "restrained modernism", while Winchester was "probably one of the most historic cities in Britain."

He described the development, which could start as early as 2007, as "a huge juggernaut heading this way".

The area to be bulldozed includes the bus station, the Marks and Spencer warehouse, Friarsgate Medical Centre, Tanner Street, Kings Walk, the former post office sorting office and Friarsgate car park.

Mr Thomas added: "A seven-storey building would be so big that it would vie with the cathedral for height, which would be a dreadful mistake. Imagine the Brooks Centre with another three storeys on top."

But civic chiefs argue that their fears are premature, as the design is still in its early stages. They stress that nothing has been decided yet. Winchester City Council is planning a series of public meetings so people can have their say on transforming the run-down central area of the city. However, critics argue that some decisions about the scale must have already been made to check it that stacks up financially.

Master planner and architect, Paul Appleton, insists the redevelopment will respect the city's historic architecture. He refused to reveal the height of the tallest buildings, but said: "What our architecture is about is finding what is appropriate for a particular place. I don't think it is right to describe us as modernists."

He added: "Winchester is about those glimpses and views of the cathedral. We will not be spoiling those, but framing them and making them better."

Allies and Morrison specialises in urban regeneration schemes and their projects include refurbishment of the Royal Festival Hall on London's South Bank along with a modern office development at Bankside and a major project in Sheffield city centre.

Developer, Thornfield Properities, is due to submit a planning application this summer for 264 flats, 40 new shops, new bus station, health centre, civic square and parking for 279 cars. Land earmarked for redevelopment which is not already owned by the city or Thornfield will be compulsorily purchased. The local authority has agreed to grant a 200-year lease to the developer.

Cabinet members are due to discuss the controversial development agreement next Tuesday. A report, to go before councillors, explains the agreement and gives a detailed timetable. There has been repeated criticism of the exclusivity deal. Barry Lipscomb, leader of the Tory group, has written to the Mayor of Winchester asking for all the papers to be made public.

Late last year, rival developers, London and Henley, declared their interest, but were effectively locked out of negotiations and have yet to submit a formal proposal.

* The next Winchester town forum will provide the first chance to see the architects' ideas for the Broadway-Friarsgate development.

Allies and Morrison will discuss their thoughts on the £100m redevelopment on February 28th. Developers, Thornfield, envisages around 40 shops and 370 homes, as well as a new bus station and public open spaces.

The forum will be held at the Guildhall, starting at 7pm. It replaces the proposed forum on tourism.