Angel di Maria
Di Maria moved to Manchester United in the summer of 2014. Getty

The latest release from Football Leaks shows that Real Madrid inserted a special clause into the deal that took Angel di Maria to Manchester United, which would have forced the Premier League outfit to pay a major figure of compensation if they subsequently sold the Argentine to another Spanish club – a clear effort to prevent him moving to Barcelona.

This is the latest deal exposed by the whistle-blowing website, after previously revealing details of Gareth Bale's record-breaking move from Tottenham Hotspur to Los Blancos in 2013, Arsenal's signing of Mesut Ozil and the salary that David de Gea could have earned at the Bernabeu if his move to the La Liga giants had not collapsed on deadline day last summer.

The contract confirms that United paid a club-record fee of €75m (£58.1, $83.1m) plus add-ons in the summer of 2014 to secure the player's services, following his impressive campaign for Real Madrid in their La Decima season.

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However, Di Maria failed to fit into Louis van Gaal's plans and last summer he was shipped off to Paris Saint-Germain, with United reportedly taking a significant loss on the player.

Football Leaks has now revealed that loss would have been much worse if he had been sold to Barcelona instead. According to the documents disclosed on 19 February, United would have been obliged to pay Real Madrid €50m if they sold the Argentinian to another La Liga side in the summer of 2015, €40m in the 2016 windows or €30m in 2017. This €30m compensation would have remained until the end of Di Maria's original contract at Old Trafford in 2019.

Furthermore, United also saved some money on add-ons due to the struggles of Di Maria to Old Trafford. Nevertheless, the Premier League giants would have paid €5m extra to Real Madrid should Di Maria been one of the final nominees for the Ballon d'Or plus a further €5m if he had received the award.

Recently Football Leaks also revealed that Real Madrid had a similar clause to complicate any potential move of Mesut Ozil to Barcelona. Los Blancos, in that case, kept a priority buy-back option that let them match any offer made by a La Liga side for the Germany international.