Gareth Bale’s agent has reacted angrily after a confidential document relating to his client’s £85m move to Real Madrid from Tottenham was leaked.

The document, released by the website Football Leaks and widely published in Spain, set out details of the full value of the deal, which has always been disputed, but which now reveals it to be a world record fee.

Real have long claimed they paid €91m (£78m) for Bale in 2013 – less than the €96m they paid for Cristiano Ronaldo four years earlier. However, the Spanish newspaper AS reported that the document showed the Bale fee amounted to a new world record of  €100,759,418 (£85m) – because Real had opted to pay in instalments – with Tottenham agreeing not to publicise the precise fee.

It is widely thought that Real wanted to keep the exact figure under wraps to appease Cristiano Ronaldo, who has always insisted his was the most expensive transfer in the history of the game.

Earlier this month the journalist Jonathan Northcroft told the BBC he was asked by Real not to mention the subject when he interviewed Bale.

He said: “Real Madrid are a club so worried about image that when I interviewed Bale it was requested to me, ‘don’t put in the article how much Gareth Bale cost’.

“The reason for that is because it was a world record transfer fee but Cristiano Ronaldo doesn’t like to see that someone else cost more than him.”

Bale’s agent, Jonathan Barnett, called the leak “outrageous”, telling the Telegraph: “There should be an inquiry and an independent investigation … I think it’s disgraceful that people can get hold of this sort of stuff. It shows complete disregard for both clubs and the player.”