Leeds United started legal action against the Football League to attempt to dismantle the collective selling of TV rights and win the right to sell their own games, The Mail on Sunday can reveal.

The extraordinary and unprecedented move has sent shockwaves across the 72 League clubs who play below Premier League level. The move could destroy a main income stream, the £100million a year they collectively earn from Sky Sports.

Although Leeds's highly controversial owner Massimo Cellino has put a temporary stay on the process, the Mail on Sunday can reveal Leeds's Championship match at home to Middlesbrough on Monday is only going ahead after the Football League was forced to take out a legal injunction against Leeds to make them honour the fixture.

Leeds United's Italian owner Massimo Cellino has started legal action against the Football League

Cellino's Leeds are arguably the 'biggest' club, in multiple ways, currently outside the Premier League.

It is believed to be the first case ever, certainly in the English game, where any governing league has had to legally force a club to play a fixture, and sources say rival clubs are aghast at Leeds' behaviour.

All 72 clubs were represented at a private meeting staged in Milton Keynes on Thursday, when the League's chief executive, Shaun Harvey, briefed them on what had hitherto been a completely secret legal dispute with Leeds and Cellino.

The clubs were told Leeds launched their initial legal to torpedo the collective selling agreement last Autumn.

Sources say executives were stunned as Harvey explained that such a challenge might theoretically destroy the league's current five-year broadcasting deal with Sky, currently in its first year.

There would be no guarantee of a Cellino legal victory, but no guarantee either he would fail either. Leeds are arguably the 'biggest' club, in multiple ways, currently outside the Premier League. If they won the right to do their own TV deals, then they would expect to hugely increase the share of TV money they receive each season from around £2m to perhaps tens of millions. Other 'bigger' clubs might follow suit and the majority would be left facing a financial deficit.

Those with knowledge of Thursday's meeting say executives from rival Championship clubs vented their fury at the Leeds representatives at the meeting - the new executive director, Paul Bell, in his first weeks in his new job, and a Leeds lawyer. Cellino was not present. Sources say Bell launched a passionate defence of Leeds's position, saying they had games moved for live TV unfairly often. Leeds's position has attracted some sympathy - albeit limited - among other clubs.

Harvey told the meeting that, for legal reasons, he was restricted in what he could say, and for legal reasons arising from Leeds's behaviour, that the League had been prevented from informing the clubs earlier about what was going on.

Cellino's desire for more TV cash for Leeds became a major public issue in December when he initially would not allow Sky cameras into Elland Road to show their match with Derby, although he backed down under pressure.

Leeds later complained bitterly about the purported 'late' move of Monday's game with Middlesbrough. Unknown to most fans, Leeds had been informed in early December that Sky wanted that fixture moved. The League could not announce that because of the ongoing legal action over collective selling. Leeds privately vowed they would refuse to play the Boro game.

Cellino's desire for more television cash for Leeds became a major public issue in December

The League were therefore forced to take drastic secret measures, applying for a legal injunction to force Leeds to honour their commitments under the Sky broadcasting contract. The League won, but the lengthy dispute meant the date could not be announced until four weeks before taking place.

This led to a backlash from fans against the League and Sky, when in fact Leeds' legal action caused the delay. Harvey told the clubs on Thursday that the legal victory over the Boro fixture 'will do nothing to repair the damage caused to the League's reputation.'

Monday's game goes ahead against this acrimonious backdrop and as one source said: 'It's one thing that Cellino is a maverick, another entirely that he is potentially threatening all of our incomes. We have no certainly when or if he might resume his attempts to smash the collective deal.'

The Football League declined to comment for legal reasons. A Leeds spokesman said they were unable to comment.