It has the potential to be summer's biggest transfer saga with Florentino Perez keen to bring the prolific England goalscorer to the Bernabeu in an attempt to kick start a 'Galacticos' comeback.
Speaking on the subject, Souness believes that the move would be necessary if Kane wants to win trophies with a new challenge the perfect opportunity for the 24-year-old to cement his place among the world's greats.
"I'm fully aware that I will be upsetting some fans with what I'm about to argue, but, being impartial, I believe that Harry Kane should leave for Real Madrid this summer if he gets the chance," he wrote. "I reckon that he could become the first £200m player".
The TV pundit argued that there will be a lack of trophy opportunity at White Hart Lane: "It's all very well playing at a new stadium, but players have different priorities".
"Big players want to be paid the going rate and win trophies. He'll be looking at wages paid at Chelsea, Manchester United and Manchester City and, although he'll never say it, knows he's better than players who are getting twice as much and winning medals."