The clubs and their fans want parity with Arsenal and Tottenham Hotspur, whose semi-final will be played at Wembley on Sunday, 4 April. Graham Kelly, the FA chief executive, said there were no reasons why the Sheffield derby, a fixture unique in the competition's history, should be re-located. United and Wednesday objected to Elland Road when the semi-final venues were first announced, but the clubs' rebellion was made public only after replays this week confirmed them as opponents.
A consensus in Sheffield fears the potential for crowd disorder would be maximised by playing the semi-final in Leeds. Many want the city's centenary celebrations enhanced by playing the Cup derby at Wembley. Roy Hattersley, the former deputy Labour leader, said Sheffield could fill Wembley 'easily'; other South Yorkshire MPs and councils said they would ask Peter Brooke, secretary of State for National Heritage, to intervene.
Wembley management said they would be 'delighted' to accommodate both matches, ideally with the Sheffield fixture on Sunday afternoon and the London derby the following night. The BBC and BSkyB said they had no objections to both games taking place at Wembley.
United and Wednesday are privately angry that the FA has ignored their warnings. 'We are not prepared to accept Elland Road as a suitable venue,' Paul Woolhouse, United's chief executive, said yesterday. 'We are prepared to play at the national stadium at any date and time suitable to the FA - Wednesday have expressed similar views.'
Protesters, many of whom said the semi-final should be boycotted unless it is played at Wembley, claim FA rules may break the law. An ad hoc campaign committee said preliminary legal advice was encouraging. 'If necessary, we are prepared to seek an injunction,' a committee spokesman said.
Elland Road would provide Sheffield fans with about 32,000 places, less than half anticipated demand. There is only one major road leading to the ground. Local police and emergency services have little experience of semi-finals, and Sheffield supporters are not familiar with the ground - Leeds have angered supporters' groups by the small allocation of places for visiting fans.
The Elland Road pitch, regularly used for rugby league, has been criticised by visiting players and managers, and Sheffield supporters resent Leeds for what they see as the extravagant and biased attention they receive from regional TV, which is based in Leeds. Police football intelligence sources confirmed that a significant number of Sheffield supporters would travel to Leeds for a Saturday night and Sunday afternoon of alcohol-fuelled mutual confrontation. Leeds supporters could be drawn in. Alternative venues, particularly with larger capacities, would reduce the potential.
The FA said it had received protests from Sheffield, but no decision had been taken to re-locate the fixture from Elland Road.
Chelsea yesterday unveiled a scheme enabling supporters to buy a share of their Stamford Bridge ground. A new company, Chelsea Pitch Owners plc, has been set up to raise the pounds 5m the club will need to buy the freehold of Stamford Bridge.
Mick Harford, the Chelsea striker who was turned down by Sunderland as a youngster, returned to his native Wearside yesterday and joined the Roker Park club for pounds 250,000.