The Football Association is coming under pressure to punish Karl Oyston for branding a Blackpool fan "a retard".
The latest chapter in Oyston's controversial reign as Blackpool chairman unfolded over the weekend when a series of foul-mouthed texts between him and Tangerines fan Stephen Smith were published online.
Oyston called Smith "a retard" and told him to ''enjoy the rest of your special needs day out.''
During the text exchange, Oyston used numerous swear words and called Smith ''educationally subnormal'' and a ''sad act''.
Smith rejected Oyston's apology on the matter and urged the FA to take action against the Blackpool chairman, whose team sit bottom of the Sky Bet Championship.
He complained to English football's governing body on Monday and it is now gathering evidence before deciding whether to charge Oyston.
"I have now officially registered my complaint with the FA," Smith told Press Association Sport.
"They haven't yet contacted me, which is a bit surprising because they have been contacted by several media organisations, but they are now supposed to be garnering evidence. I hope they come to me."
Mental health charity Mencap called on the FA to take action against Oyston.
''I am glad Karl Oyston has apologised but using the language that he used is never justified," said Ismail Kaji, who works for Mencap.
''I have a learning disability and am a big football fan but I would feel ashamed to support any football club that has a chairman who uses such unacceptable language to people with a disability. This language is just as bad as using racist or homophobic words and I hope the FA treats this as seriously.''
Oyston should brace himself for a protest against his regime at Blackpool's game on Boxing Day at Sheffield Wednesday, according to Smith, who is a spokesman for the Tangerine Knights group which published the messages on their Facebook page.
''I think it is perfectly clear the fans are going to make their opinions heard and that will be done at the next match,'' Smith added.
''His apology is weak. His position as chairman is untenable. He has no choice but to resign.''
The Tangerine Knights published another series of text exchanges reported to be between Oyston and Blackpool fans on Monday night.
In those messages, Oyston reportedly makes a series of serious allegations against former manager Jose Riga and appears to criticise other supporters who contacted him after his phone number was published online.
The group has since removed the latest batch of messages from its Facebook page.
Earlier on Monday Oyston said the fact that he had received a number of abusive messages led him to respond in the way he did.
"I would like to unreservedly apologise for any offence or distress caused by my text responses reported in the media recently,'' Oyston said in a statement.
''I regret stooping to the level of those threatening and abusing my family.
''My mobile number was placed on a social media website recently and it led to a barrage of abuse about my mother, father, wife, children and myself.
''In hindsight the aim of this was clear, and I foolishly opted to challenge some of the abuse, harassment and threats.
''Given my position, I should have acted with more responsibility and reported the abusive text messages, phone calls and answer phone messages to the police, rather than get embroiled in such an exchange.''
Source: PA
