Cristiano Ronaldo wants to leave Real Madrid, according to reports in his native Portugal, in a decision that has been described as "irreversible".

The 31-year-old former Manchester United winger is reportedly angry at his treatment by Spanish tax authorities and wishes to leave the country, according to the front page of Portuguese daily A Bola on Friday.

Ronaldo is the subject of a lawsuit brought by Spanish prosecutors over tax that they believe he should have paid on image rights income. The winger is being accused of defrauding nearly €15m from the taxpayer.

Ronaldo's Champions League century Show all 21 1 /21 Ronaldo's Champions League century Ronaldo's Champions League century Ronaldo's Champions League century Against Bayern Munich, Cristiano Ronaldo became the first ever man to score 100 goals in the Uefa Champions League. Here we recount some of his most memorable. Getty Images Ronaldo's Champions League century Goal 1 Ronaldo opened his century of Champions League goals against Debreceni in the third round of qualifying for the competition. He netted a precise tap in off a Wayne Rooney cross off the right flank. AFP/Getty Ronaldo's Champions League century Goal 9 An injury time free-kick from 20-yards out against former club Sporting secured a 2-1 win for Manchester united in the 2007 Champions League group stages. Man Utd via Getty Ronaldo's Champions League century Goal 12 A towering 26th minute header in the 2008 final gave Manchester United a vital early lead. The Reds went on to beat Chelsea 6-5 in penalties. Getty Images Ronaldo's Champions League century Goal 15 Still to this day one of the finest goals in Champions League history. A 35-yard screamer from open play against Porto gave Manchester United the a 3-2 aggregate win in the quarter-finals. Getty Images Ronaldo's Champions League century Goal 40 Ronaldo's 90th-minute strike won an engrossing game as the nine-time champions scored twice in the last four minutes to snatch a 3-2 victory. Getty Images Ronaldo's Champions League century Goal 43 A cheeky chip over goalkeeper Kenneth Vemeer gave Ronaldo his first Champions league hatrick as Real Madrid thumped Ajax 3-1 in the second group stage match in 2012. Getty Images Ronaldo's Champions League century Goal 44 A second chip in two matches- this time Ronaldo latched on to a long ball in the box before sneakily flicking over Borussia Dortmund keeper Roman Widenfeller for the equaliser. AFP/Getty Images Ronaldo's Champions League century Goal 50 50 up in style! Six minutes into the 2012/13 Champions League quarter-finals first leg against Galatasaray, Ronaldo found himself in space to convert Karim Benzema’s cross, putting Madrid one step closer to what was a record 24th European semi-final. AFP/Getty Images Ronaldo's Champions League century Goal 54 Ronaldo and Real Madrid ran riot against Galatasaray in the 2013 group stages. A jaw dropping dribble weaved through the Turkish defence and a low blast past the outstretched hands of Fernando Musrela brought up Ronaldo’s second European hatrick and helped them to a 6-1 win. Getty Ronaldo's Champions League century Goal 62 This time Schalke were at the other end of the Ronaldo and Madrid show. He strormed down the centre field, split the defence in two, dribbled the keeper and scored his second of the night. Simple. Bongarts/Getty Images Ronaldo's Champions League century Goal 64 The second leg of the 2013 Champions league round of 16 against Schalke brought about another Ronaldo double. A 30-yard run down the right wing and a shot from the edge of the box gave the keeper no chance. Madrid completed a 9-2 aggregate win over the Germans. Getty Images Ronaldo's Champions League century Goal 68 The night Ronaldo won the Champions League for Real Madrid. He lined up for the 120th minute penalty and made no mistake. Real Madrid scored 4 goals in extra time to break Atletico hearts. Getty Images Ronaldo's Champions League century Goal 73 Ronaldo's 73rd European goal came at Liverpool. Despite not being as instantly brilliant as some of his others, it was voted the second-best goal in the competition that season and set Real on their way to a comfortable 3-0 win at Anfield. AFP/Getty Images Ronaldo's Champions League century Goal 80 A classic Ronaldo penalty brought up the personal milestone of 80 European goals and helped but was not enough to send Real through to the finals of the Champions League. Getty Images Ronaldo's Champions League century Goal 83 After Marcelo’s shot was saved by the keeper, Ronaldo was in the perfect spot for a rebound and in the process brought up his third European hat-trick vs Shaktar in the 2015 Champions League group stages. Getty Images Ronaldo's Champions League century Goal 90 An 8 goal drubbing of Malmo gave Ronaldo his fourth European hat-trick. The third goal from the three came in the 59th minute from a low blast through the keepers legs. Getty Images Ronaldo's Champions League century Goal 91 With his fourth goal of the match against Malmo, Ronaldo broke the record for the most goals in the group stages of the Champions League (11). Getty Images Ronaldo's Champions League century Goal 92 A game later against Roma, Ronaldo ventured down the left leaving the defence trailing. One quick cut in and a curved right foot shot later and he had his 92nd European goal. Getty Images Ronaldo's Champions League century Ronaldo’s fifth European hat-trick came against Wolfsburg in the 2016 quarter-finals. The Germans had won the first leg 2-0. He completed the stunning comeback with a sublime chipped free kick that sent the Madrid fans into delirium. Bongarts/Getty Images Ronaldo's Champions League century Goal 100 The Real Madrid superstar scored five of his team's six goals in the quarter-final tie against Bayern Munich, moving him to a century of goals as he tapped home Marcelo’s cross in the second period of extra time. Getty Images

Real Madrid issued a statement fully supporting the player, claiming they were "absolutely convinced of his innocence."

The Portuguese legend this month won his third Champions League as a Madrid player, and fourth of his career, but is so "indignant" at what he feels amounts to persecution that he is ready to walk away, and has communicated that decision to Florentino Pérez, the Real Madrid president.

A Bola recently also claimed that Ronaldo would be the subject of a €180m bid this summer, suggesting this outcome may have been in the pipeline for some time.

Paris Saint-Germain have been long-term admirers of the Madeira-born star and held a number of secret meetings with him over a transfer during the 2015/16 season. Club president Nasser El-Khelaifi would jump at another chance to sign Ronaldo, even if there were suggestions he leveraged PSG's interest to boost the multi-million euro contract extension he signed last year.

Manchester United, too, would be keen on bringing Ronaldo back to Old Trafford. Ed Woodward remains obsessed by star appeal and signing football's biggest individual brand would tick every box as United look to return to being title challengers.

With the collapse of their move for Antoine Griezmann and Andrea Belotti proving too expensive, Ronaldo could be the perfect tonic for United even if it is hard to imagine a scenario where Ronaldo decided to leave Madrid and United hadn't already been informed.