The Tottenham Hotspur chairman, Daniel Levy, has urged the Premier League to "review the system" after watching two of his club's biggest names leave against his wishes this summer.

Spurs have agreed not to pursue a complaint against Manchester United for allegedly making an illegal approach to Dimitar Berbatov, after selling the Bulgarian striker for £30.75m on Monday. However, they remain far from happy about the way Berbatov left. They were similarly perturbed by Liverpool's ultimately successful pursuit of Robbie Keane.

"There are no guarantees in football and this summer we found ourselves having to deal with the unexpected challenge of both our leading goalscorers making it clear they wished to leave the club," Levy said. "I have already stated my opinion on the manner in which our players were approached and the nature of the negotiations surrounding Robbie Keane and Dimitar Berbatov. [Monday's] events were further evidence of the need for the Premier League to review the system. I have also previously said that we had no need to sell players on long contracts. This no longer remains practical."