The 24-year-old was selected as skipper in both of England's last two matches, against Slovenia and Lithuania, and struck the decisive goal in both of those 1-0 victories.
A United source is quoted as saying: "The club had asked about Kane's availability a few years back".
He believes a potential partnership with Romelu Lukaku could turn United into a dominant European force again.
"If they say yes, Harry will get the chance to speak to them and I'm sure if he walks into the Bernabeu with an opportunity to sign, he'd find it very hard not to". Jose is a big fan and is very interested.
They are said to be adamant all approaches for their star players, including Kane, will be turned down.
"It's money they can lay their hands on but it will be interesting to see what Levy's stance on the whole thing will be".
However, Tottenham are planning to try and make their own statement regarding Kane's future, with The Sun adding that Spurs hope to open talks with the Englishman next summer about agreeing a new contract worth £150,000 a week.
Kane's current deal at Tottenham expires in 2022 and the club insist he is not for sale, but Real Madrid are also reportedly interested in making a move for the frontman.
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