The 34-year-old midfielder has never hidden his desire to end his career with his boyhood heroes, and Celtic now appear to be leading the chase for his signature after Real Madrid cooled their interest yesterday.

He parted company with Manchester United last month, sparking furious debate over his future since then.

But Rafferty believes one thing is certain: Keane still has plenty to offer at the highest level.

“He would be a great signing for Celtic and Iink most Celtic supporters would love to see it happen,” he said.

“It has been well-documented that he is a Celtic fan and he has been spotted on many occasions at European ties and Old Firm games at Parkhead.

“However, the most important thing is that he is a good footballer and his track record proves that.

“He is a winner and that’s important.”

Celtic crashed out of Europe at the first hurdle this season and were forced to look on enviously as Rangers became the first Scottish club to progress from the group stages to the last 16 of the Champions League.

But Rafferty believes the addition of Keane could make all the difference to their European hopes next term.

He added: “He is a first-class player in the modern game and has played at the highest level in England and in Europe. He has all the criteria.

“If we could acquire him, he would be a major addition for the Champions League next season.

“You need someone with a winning mentality and ability – and he has that in abundance.”