Markanday was highly rated at Spurs and the club wanted to keep him in their ranks, offering him a fresh contract to do so.
But the 20-year-old struggled to break into the senior team under new boss Antonio Conte and decided to pursue first team football elsewhere, snubbing the new deal.
Championship side Blackburn pounced to snap up the attacker, sealing a permanent move for him on a three-and-a-half year deal.
Rovers had been tracking Markanday for some time and saw an opening to take him to Ewood Park once he opted to not extend his stint at the capital club
Tottenham only earned a nominal fee from Rovers for Markanday, but they could make more profit from the deal in the future.
The north London giants have managed to insert a large sell-on cause in their academy graduate’s deal to join Blackburn.
And as such Tottenham are entitled to receive a significant chunk of any fee Blackburn will receive if they sell Markanday.
The winger will now link up with Rovers boss Tony Mowbray and help the club in clinching automatic promotion to the Premier League or at least a playoff spot.