The market, the prince, and the dark mutterings of conspiracy

Once, they were a hive of activity, as beef, pork and lamb was bought and sold in their vast halls. Now the cries of the market porters are a distant echo as three buildings, which once formed part of Britain's biggest market complex, lie silent.

Once, they were a hive of activity, as beef, pork and lamb was bought and sold in their vast halls. Now the cries of the market porters are a distant echo as three buildings, which once formed part of Britain's biggest market complex, lie silent.

But these symbols of Victorian London have become a battleground in a fight which crystallises the debate over the future of Britain's endangered buildings. And one which has now, thanks to the involvement of the Prince of Wales, acquired a whiff of conspiracy theory.

On one side are the traditionalists, who argue that the buildings should be preserved and restored to function again as a market and community focus.

Facing them are the modernisers, led by the development company Thornfield Properties, which plans to build a multimillion-pound complex, creating half a million square feet of office space and a new "urban market hall".

Caught in the middle is the City of London Corporation. It accepts the special nature of the site while pointing out the need for extra office space in the area.

But the process could be derailed by a decision later this week from the Heritage minister Lord McIntosh of Haringey, who is to announce whether the buildings are to be given listed status, preserving them, in effect, from development.

The three buildings, erected in the late 19th century, were once part of the Smithfield markets area. The general market and its adjacent annexe or fish market, were designed by the Sir Horace Jones. Both were intended for other produce, but were eventually taken over by the sale of meat and poultry. Both fell out of use during the 1990s as supermarkets came to dominate the trade. The third building, the Red House, which operated as a cold store, has been out of use for about 20 years. Meat trading continues in the remaining parts of the markets.

Prince Charles is known to have made "private representations" to some of those involved, although in what fashion remains unclear. A spokeswoman for the Prince said: "He not only believes the buildings are an important part of London's heritage but he also believes they can be restored for the benefit of the local community.''

The message could not be clearer to Tessa Jowell, the Culture Secretary, who, as Lord McIntosh's boss, would rubber-stamp the listing. Enter the conspiracy theorists. The Prince accorded Ms Jowell the honour of a kiss on both cheeks when greeting her at the opening of the memorial to Diana, Princess of Wales in Hyde Park - something reserved for family and very close friends. Could it be, it was suggested, a sign of his desire to win her over to his side?

The second aspect of the conspiracy theory is that English Heritage, which advises the Department of Culture, Media and Sport on listing, was asked to consider the matter again this spring, only a year after it last concluded that the buildings, because of bomb damage suffered during the Second World War and subsequent alterations, did not meet the strict criteria for listing.

The department has now consulted English Heritage four times in 15 years on the site and on each occasion accepted the advice not to list. If either changes its mind, it will be seen as evidence of royal pressure. The department rejects the advice of English Heritage in less than 1 per cent of cases.

The lobby group Save Britain's Heritage says the buildings are a crucial part of Britain's heritage, equivalent to the great markets of Europe.

Michael Capocci, managing director of Thornfield, said: "We would open up the area, creating a new market, with buildings which will be listed in 30 years time. We want to be judged on our plans, without all this black propaganda.''

A decision will be announced next week. Sources at the culture department say it could go either way.