The 25-year-old can play on for now, as he has 16 days in which to decide whether to appeal against his punishment.

But an eight-month ban would mean Ferdinand missing the remainder of Manchester United’s season and the Euro 2004 finals with England.

The FA's independent commission spokesman Nick Baron confirmed in a short statement: "The commission unanimously found that the charge was proved against Rio Ferdinand.

“It was further decided that he be suspended for eight months from January 12 2004 and fined a sum of £50,000 (€71,333).

“Having requested a personal hearing, he is subject to pay the costs of the hearing.

“Such decisions are subject to the right of appeal.”

If Ferdinand decides not to appeal against the eight-month ban he will be available to play in United's next six matches.

He would be able to play in Premiership matches against Tottenham (away on Sunday), Everton (home on St Stephen's Day), Middlesbrough (away on Sunday, 28 December), Bolton (away on Wednesday, 7 January) and Newcastle (at home on Sunday, 11 January) and the FA Cup third round tie away to Aston Villa on Sunday, 4 January.

Tonight’s decision follows 18 hours of deliberation over the past two days.

Evidence was heard by the FA’s three-man disciplinary commission of Barry Knight, Peter Herd and Frank Pattison.

Those called included Ferdinand himself, his manager Ferguson, club doctor Mike Stone and Manchester City midfielder Eyal Berkovic.

The hearing – the most controversial the FA have had to deal with since Eric Cantona leapt into the crowd at Selhurst Park eight years ago – was preceded by a visit for the disciplinary panel to United’s training ground.

Mark Gay presented the case against Ferdinand, whose defence was provided by Ronald Thwaites QC and who was flanked by United director and legal expert Maurice Watkins when he arrived to give his evidence.

PFA chief executive Gordon Taylor, who has been so critical of the FA’s handling of Ferdinand’s case, was also in attendance as an observer.

Mark Gay opened the first two-hour session, outlining the case against Ferdinand, whose defence was being presented by Ronald Thwaites QC, assisted by Watkins.

Ferdinand, who has never tested positive for any banned substance, eventually provided a sample on September 25 – and that proved to be negative.

The FA have been widely criticised for letting the case drag on for almost three months from the day Ferdinand failed to show for his test until the start of his hearing.

FIFA chief executive Sepp Blatter was among those to condemn the FA most vigorously and hinted he would be prepared to increase the eventual punishment should he deem it not to be severe enough.

The FA’s position was made no easier by the fact that Manchester City midfielder Christian Negouai was merely fined for a similar offence earlier this year.

Negouai’s case came to light only in the wake of the storm which erupted over Ferdinand’s failed test, which became public knowledge when he was ditched from England’s Euro 2004 squad to face Turkey in October.

That move came despite fierce opposition from national team boss Sven-Goran Eriksson, who was among those to have provided written character references for the player.