The Wales international moved to Real Madrid in a £85.3m deal from Spurs five summers ago after Bale won the PFA player of the year award in April 2013.
The 28-year-old has won four Champions League titles, the Copa del Rey and the La Liga title during his spell at The Bernabeu.
Real Madrid are looking to sign a world class player in the summer transfer window to appease Madristas following Cristiano Ronaldo’s £100m switch to Serie A giants Juventus.
Harry Kane has been linked with a potential switch to Real Madrid this summer following an impressive 30 goals in 37 games in the Premier League last term.
Sunday Times reporter Castles revealed that Real Madrid are prepared to offer Spurs the chance to sign Bale in a potential deal that would see Kante make the switch to The Bernabeu.
“They have been told Kane is not for sale,” Castles told the Transfer Window podcast.
“It has been suggested to me that Real Madrid would be willing to offer Gareth Bale and around €150m for Tottenham but in the knowledge Bale isn’t keen on going back to Tottenham.”
Manchester United finished in second place in the Premier League table last season to ensure their continued participation in the Champions League.
The Red Devils have signed Shakhtar Donetsk midfielder Fred and FC Porto defender Diogo Dalot in the summer transfer window so far.
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