Neil Warnock has claimed refereeing standards in the English game have gone backwards under referees' chief Mike Riley.
Cardiff manager Warnock could yet receive a Football Association charge over his post-match comments about the officials following the controversial 2-1 Premier League defeat to Chelsea on Sunday.
But Warnock was defiant in his criticism of Riley, head of the Professional Game Match Officials Limited, before Cardiff's visit to Manchester City on Wednesday.
"I always thought Mike Riley was a manufactured referee from day one," Warnock said.
"I don't think he's changed since then. He's been coached manufactured, almost like a robot.
"He knows everything about the rules, but I feel these people struggle to understand the game and the human element.
"A lot of referees are like Mike Riley and that's why I think we have gone backwards."
"Common sense thing is not allowed nowadays, but the best refs still use it.
The Independent has asked the Premier League and the Referees' Association for a response to Warnock's comments.
It is understood that Warnock will escape punishment for his on-field behaviour after standing and shaking his head as referee Craig Pawson and his assistants left the pitch after the Chelsea game.
