Wolves boss Nuno Espirito Santo has been charged by the Football Association for his recent criticism of referee Lee Mason.

Nuno said after Wolves' 2-1 defeat at Burnley on 21 December that Mason "is not good enough" to officiate at the top level.

The Portuguese manager subsequently refused to apologise for his comments.

The FA allege his comments "constitute improper conduct" as they were "personally offensive" to Mason.

Nuno has until Tuesday, 5 January to respond to the charge.

Before the charge was announced, Nuno said he regretted the "timing" of his criticism but that he would "never question the integrity" of an official and was making a comment on the "ability" of the referee.

Under current FA regulations, post-match comments that criticise the performance or competence of a match official are permitted unless they imply bias, attack the official's integrity, are personally offensive, are prolonged, or are particularly unreasonable.