Smithfield market inquiry to open after protests against £160m redevelopment

Save Britain's Heritage calls McAslan plan for office and shops 'worst mutilation of a major Victorian building in 30 years'

A small boy grapples with a dolphin above the entrance to Smithfield General Market in the City of London, blissfully unaware that he'll soon have bigger fish to contend with. The majestic complex of brick and cast-iron market halls, which have stood here since 1883, but lain derelict for the last 15 years, are facing a controversial £160m plan to scoop out their innards and insert six-storey blocks of shops and offices in their place. It is a plan, in the eyes of its critics, akin to squeezing a whale inside a minnow.

"It would be the worst mutilation of a major Victorian building in 30 years," said Marcus Binney, chairman of Save Britain's Heritage, which has campaigned against the scheme with the Victorian Society and others, prompting Eric Pickles to order a public inquiry, which begins on Tuesday. "The architects talk mischievously and misleadingly about 'dismantling' and reusing parts of the building, but it's a complete sham. They are destroying the grandest parade of market buildings in Europe."

The proposals, designed by architect John McAslan for the international investment firm Henderson Global, will retain the brick-and-stone perimeter buildings, and insert three blocks in the centre of the complex, rising up to 20 metres and providing over 21,000 square metres of office space and 5,700 square metres of shops.

"We are retaining as much of the existing buildings as we possibly can, but it has to be a viable scheme," said McAslan, who has a track record of intelligent intervention in historic structures, from the Camden Roundhouse to the recent restoration and extension of King's Cross station. "It's not just a facade job – we're keeping the entirety of the Fish Market and reusing most of the original columns and beams, while the whole ground floor will be open for retail. Around 75% of the existing fabric will remain."

The buildings in question, which stand to the west of the still-functioning meat market, are the work of Horace Jones, the City of London's surveyor from 1864 to 1887 and architect of Billingsgate and Leadenhall markets, as well as Tower Bridge.

"It is his finale," says Binney. "He upped his game at the end of his career and introduced these wonderful Phoenix columns [a very strong yet light wrought-iron column that allowed greater distances to be spanned] from America, topped with Egyptian capitals. It's a really noble space of lattice girders and arched trusses, topped with a fine postwar saucer dome – and the whole lot is being ripped out."

Save Britain's Heritage and the Victorian Society, who together have gathered over 10,000 signatures of support, have submitted an alternative planning application to transform the complex into a public market and workspaces. The plan is backed by Eric Reynolds of Urban Space Management, who established Camden Lock market in the 1970s and masterminded the rejuvenation of Spitalfields in the 1990s – both then derelict, now thriving.

"We want it to be more than just a market," says Reynolds. "There will be food and clothes, but also workshops and studios, drawing on the traditional clockmaking and silversmithing industries of the area."

The plan is costed at about £16–18m, to be funded by market rents, as at Spitalfields, with a potential later phase planned to open up the atmospheric netherworld of basements that spread below the market halls. "London is increasingly full of the usual clone outlets, but this would be a place of idea exchange," says Reynolds. "It may sound wet and wobbly, but it is what makes places interesting."

Labour's parliamentary candidate for the area, Nik Slingsby, has come out in support of the scheme, joining a star-studded list of backers, from Alan Bennett to Kristin Scott Thomas.

"If you go to St Bartholomew's and then walk through Smithfield, it is like walking from one cathedral to another," said Bennett. "You wouldn't pull down St Bartholomew's, nor should you pull down Smithfield. Smithfield was the scene of many martyrdoms – this would be another."