Heritage campaigners have called for a public inquiry after plans to build a seven-storey office block next door to one of London's most famous landmarks were given the go-ahead.
The "general market", which was built in 1883 and designed by Sir Horace Jones, sits on the west wing of Smithfield meat market.
Campaigning groups had tried to gain listed status for the building, arguing that it forms part of Britain's most impressive group of market buildings. But following their failure to achieve this, the City of London Corporation, who own the market's lease, has agreed to grant planning consent to the developers, Thornfield Properties plc. If the plans are ratified by the Government, demolition of the historic site could begin after three weeks.
The project will see the building knocked down and replaced by 350,000 sq ft of office space, with a retail outlet on the ground floor.
English Heritage said it "strongly objected" to proposals to grant planning permission, and said it agreed with the sentiments of a letter written by Tessa Jowell last year to the Office of the Deputy Prime Minister, suggesting a public enquiry into the future of the Smithfield market building.
A statement from English Heritage said: "We have called on the Secretary of State [Ruth Kelly] to call in the case, and await her response. Like Oxo Tower, Tate Modern or Borough market, this building is one of many well-loved and useful buildings which are not listed, but which are still a very important part of London's architectural and historic character.
"English Heritage often supports new development schemes and is disappointed that the proposed new building is so poorly suited to the area. This design is not top quality and instead of encouraging small business and diversity, it destroys the bustle and creativity of the area with an enormous single-use office block."
Save Britain's Heritage said it would be grave if a building of such historical significance was destroyed. Adam Wilkinson, the campaign group's secretary, said he was urging the public to write to the government to ask for a public enquiry.
"It is the most fantastic complex of historic market buildings in the country," he said. "The development would completely destroy it and rebuild seven storeys rather than two storeys. It would not give life to the area and it would just join the great, big, dull wall of office buildings on Farringdon Road. It is completely at odds with the other market buildings in terms of its size."
Matthew Saunders, from the Ancient Monument's Society, said the although the present set of buildings in Smithfield were part of a 19th-century rebuilding project, the site itself was "one of the oldest markets in the country, going for centuries from the beginning of the Middle Ages".
At present, there are rail tunnels beneath the buildings which are in need of repair. But Mr Saunders said there were other ways in which they could be accessed without demolishing the entire building.
"When a Tube tunnel needs repair, we do not have to demolish a whole building," he said. "This is a terribly crude way of mending the Tube and we would end up demolishing half of London. I am sure there is scope for a partial redevelopment, in which part of the building such as the front is left intact, but more radically redeveloped inside."
But Michael Capocci, the managing director of Thornfield Properties, said he hoped to move forward with the development at the earliest opportunity.
He said: "It has taken us over five years to get to this point and we have been painstaking in ensuring that all the planning and design requirements have been met. We have also consulted widely on our proposals.
"The resulting design enhances the Smithfield Conservation Area and makes a lasting contribution to the regeneration of the area."
A spokesman added that the modern office block would be designed to blend with Smithfield and that it would create easier access to the meat market.