The resignation of referee Pierluigi Collina has left many Italians wondering whether the sport’s best-known match official was forced to quit.

Collina resigned from the Italian Association of Referees (AIA) on Monday after refusing to forego an €800,000 per year sponsorship deal with German car manufacturer Opel.

The Italian Football Federation (FIGC) had accused him of a conflict of interest because Opel is also one of the main sponsors of Serie A title Milan.

Meanwhile, FIGC president Franco Carraro remains hopeful that a compromise can be reached.

“I am an admirer of Collina and I’m grateful for all he has given to Italian football,” Carraro was quoted as saying in La Gazzetta dello Sport on Tuesday.

“I am glad that the president of the AIA (Tullio Lanese) has decided to turn down his resignation. All we can do now is see what happens next.”

Collina turned 45 in February, the retirement age for referees, but was allowed to continue for another year after the FIGC intervened to change the rules in recognition of his status.

According to Lanese, Collina visited him shortly after the end of last season to discuss the Opel deal.

“On July 17 Collina came to me to talk about the sponsorship deal. I told him, ‘Great, well done, good luck,’ but that didn’t mean I wanted to authorise it,” he said.

Collina’s decision to quit came as a surprise.

“I met him at Viareggio and I saw that he was upset, but I did not think he would do so far,” Italy coach Marcello Lippi said.

Fabio Capello, coach of champions Juventus, had no problem with Collina being sponsiored by Opel.

“A person’s credibility does not depend on who sponsors him,” Capello said.

“I feel bitterness for a decision that has deprived us of a man of sport who has always been fairness and up to the job.

“I believe Collina was offended – that was why he took this unexpected decision. I hope he reconsiders because Italian and world football would lose a great referee.”