The Sun says Hart is heading for a contract bust-up with Manchester City - and it has put Spurs on red alert.
New City boss Mark Hughes faces a headache as keeper Hart is furious with the big-spending club's latest offer.
Hart, 21, is among the lowest paid stars at Eastlands and reckons he is not valued highly enough.
He earns around £10,000 a week while the likes of Martin Petrov and Vedran Corluka pocket £50,000-plus.
A City source revealed: "Joe is really annoyed. He wasn't expecting fortunes but simply to be paid what he feels he is worth after establishing himself among the best around.
"He can't understand why City appear to be regarding his services so lightly. He feels what was put in front of him to sign was a real insult."