A source claims the "outraged" Portugal international "feels great indignation" with all the speculation about his tax affairs and a sense of "injustice" at the allegations - which he contests - and has made a decision to leave Spain.

Earlier this week Ronaldo's agency Gestifute released a statement which said: "'There is no tax evasion scheme ... There has never been any hiding nor any intention to hide anything."

On Thursday Ronaldo, who only signed a new five-year contract in November, posted a picture of him with his fingers to his lips on Instagram with the caption: "Sometimes the best answer it's to be quiet."

The potential availability of the Portugal international, one of the most marketable players in the world, would alert a number of top clubs, plus big-spending Chinese Super League sides looking to make a statement.

However, his Real contract is understood to have a €1bn buy-out clause and, in May, Forbes calculated his pre-tax salary as being close to €51m a year.

Ronaldo has helped Real win the Champions League three times, scoring twice in last month's final as they became the first club to retain the title and he only the second player to score in three different finals. He is also the competition's record goalscorer with 105.

He has also won two LaLiga titles with the club he joined from Manchester United for €91m in 2009.

Arch-rival Lionel Messi took a similar stance in threatening to quit Spain in 2014, also claiming he had been singled out for special treatment, when he was accused of concealing €4.1m from the authorities.

The Argentina was found guilty and subsequently lost an appeal against a 21-month prison sentence - under Spanish law sentences under two years are usually suspended - and a €2.1m fine.

- PA