(Photo by Clive Rose/Getty Images)The uncertainty over Harry Kane’s future is set to drag on into next season as Tottenham Hotspur are unwilling to let the striker leave this summer, according to Sky Sports.Kane, 29, will be out of contract in July 2024 unless he signs a new contract, where he became their all-time top scorer last month by scoring his 267th goal for his boyhood club.The England captain has been linked most recently with strong interest from Manchester United and Bayern Munich. However, if Spurs are unwilling to sanction a transfer before the start of next season, those clubs may have to look elsewhere for a top centre-forward.A source has told ESPN's Mark Ogden this week that United will not risk a prolonged pursuit of Kane that drags out until final hours of the summer transfer window."United can't afford to start the season without a new striker," the source said. "And having dealt with Levy in the past, they don't want to go through that nightmare all over again for Kane with so much at stake, so they might not even get involved."If Kane still does not sign a new deal, he would be able to open talks and sign a pre-contract with foreign clubs from next January and leave Spurs as free agent at the end of next season.