The pair were charged in relation to comments made following United's FA Cup defeat by Portsmouth on March 8. Ferguson's charge concerned comments about referee Martin Atkinson and referees' chief Keith Hackett, while Queiroz's charge related to comments about Atkinson.

However, at an independent regulatory commission hearing on Wednesday the charges were found 'not proved'.

The FA have confirmed they have the option to appeal - and refuted suggestions a transcription error led to the commission finding the pair not guilty.

The governing body will await receipt of the full judgement and 'written reasons' before considering further action.

As for suggestions their case failed because their belief Queiroz described Atkinson as a 'robber' proved to be incorrect, the FA insist the charge did not centre solely on that alleged comment.

"The charges were brought on more than just the issue of the word 'robber'," said an FA spokesman.

"At any disciplinary hearing the FA, as the prosecutor, argues its case, as does the defence. The fact that the commission found the charge was not proved does not mean that the FA made any errors in putting the case together.

"The commission has to make a decision based on the applicable standards of proof, which is balance of probability."

Speaking after Sulley Muntari's penalty gave Pompey a shock victory at Old Trafford, Ferguson felt his side had earlier had a blatant spot-kick denied when Cristiano Ronaldo was blocked by Sylvain Distin.