And one Italian club has directly accused Sir Alex Ferguson's club of 'robbing' them of their talented players.
With Chelsea banned from signing players until 2011 after being found guilty of inducing 15-year-old Gael Kakuta to break his contract with French side Lens, clubs in Holland as well as Italy have joined the chorus of condemnation at the tactics used by Premier League clubs to recruit youngsters.
UEFA president Michel Platini is in talks with the European Commission, hoping to introduce a ban on the transfer of players under the age of 18 by 2011. But it will be too late for Empoli director Giuseppe Vitale, whose teenage stars Alberto Massacci, 16, and Manuel Pucciarelli, 18, joined United last month. Vitale said:
'We are not happy. Manchester United do this kind of thing a lot because they know our regulations in Italy, whereby we cannot put our youth players on lucrative contracts. They didn't speak to us about our players. It is not right and they know it is not right.
'Platini must change the law so that when a big club come in and try to rob - and that is the right word, rob - us of our players, they must pay us a decent amount of money.'
Roma director Bruno Conti, whose club lost 16-year-old David Petrucci to United last year, said:
'United are still behaving in this way. It is not sport and it is no way for Sir Alex Ferguson, one of the game's great leaders, to conduct himself.
'We invest a lot in these young players in both time, education and money. The law still allows them to do that but Michel Platini is already in talks with the Italian FA to look at ways to eliminate this.'
AZ Alkmaar president Dirk Scheringa, whose club have lost 17-year-old Vincent Weijl to Liverpool and Oguzhan Ozyakup, 15, to Arsenal, said:
'Morally, it is a terrible thing that the biggest talents were taken from us like that.'
Scheringa has called for the rules to be changed after admitting that Liverpool and Arsenal haven't broken the current ones.