"I just knew at the time I was signing that it wasn't the right decision and something I wasn't 100% sure that I wanted to do," he said.

"At the time, I thought it was what I had to do but with hindsight it was not what I wanted.

"Four or five months previously, I really let the contract situation get to me and I just made the wrong decision.

"I didn't handle the pressure of the contract running out and negotiations not happening or not going very well.

"The closer it got to the end of the contract, I didn't enjoy that.

"I think my agent at the time did his job. He tried his best to get me the best deal at Celtic but unfortunately the two sides couldn't get together.

"I think I should have made a different decision.

"If I did it again, I would have taken a more hands-on role with negotiations."