Manchester United boss Jose Mourinho has ruled out any chance of roping Cristiano Ronaldo back to Old Trafford, says it is a 'mission impossible'.

Ronaldo's future at Real Madrid has been thrown into doubt over allegations that he evaded paying £12.9million in tax.

The Portuguese superstar is due to appear before the court at the end of the month and has been described as 'angry and hurt' by Madrid president Florentino Perez.

It emerged that Ronaldo held secret talks with Paris Saint-Germain president Nasser Al-Khelaifi before Madrid retained the Champions League by beating Juventus last month, and that has re-ignited speculation over the possibility of a return to United.

The 32-year-old left Old Trafford for Madrid in 2009 after six seasons in English football.

'I'm not going to waste my time thinking about players who are mission impossible,' Daily Mail quoted Mourinho.

'We have never thought about it because he is such an important player for his club, of great economic power. We have not been able to find for whatever reason that could have made us think Ronaldo could leave.'