Some of the Premier League’s top clubs have become embroiled in a row about poaching after agreeng an unofficial amnesty behind the scenes, in a move that has led to complaints from Manchester United and means serial offenders can expect to go unpunished.

United are unhappy that at the last meeting of the Premier League’s shareholders a gentleman’s agreement was made that any club who have been guilty of using underhand tactics in the past should not face action if they admitted it to the authorities. “This is to the discredit of the Premier League,” a high-level Old Trafford source told the Observer. “If clubs have been guilty of wrongdoing they should be punished.”

Although there was no official vote, it was agreed to have what was described as a moratorium period, taking in any case up to November, at a time when the league are gathering information about new ways to prevent clubs enticing away the best youngsters from their rivals with financial offers. As well as United, several other clubs including Liverpool and Tottenham Hotspur believe they have lost highly promising academy players to unscrupulous methods.

As part of their background work, league officials intend to speak to the relevant clubs about the tactics employed and felt it important to do so on the basis that whatever they heard was not punishable unless there was an official complaint. That way, the investigating team believe they will get a better idea of what goes on and, in turn, work out a system to prevent it happening in the future.

United’s information is that they have lost some of their most talented youngsters because other clubs have bought them houses as well as offering to pay for their siblings to be educated at fee-paying schools.

In another case, involving a London team, one young player was moved into an exclusive estate near the club’s training ground and his mother was given a job working at the stadium.

United have been involved in several tapping-up controversies in the past and could be seen as opening themselves to allegations of double standards by expressing their dissatisfaction with the process. However, the current regime are unimpressed that clubs can now confess to taking part themselves or highlight cases where they have been the victims, without it meaning the possibility of disciplinary charges.

Behind the scenes, United’s relationship with Manchester City has suffered at academy level over the last couple of years, amid disquiet at Old Trafford about the way some of their more promising youngsters have gone to their rivals. Yet they have never made a complaint and the relevant people at City have privately questioned whether they are the victims of a deliberate smear, at a time when United are widely recognised as having fallen behind their neighbours at academy level. City have always utterly refuted any wrongdoing.

New rules are likely to be brought in and, in future, it may be that parents can be interviewed and have to declare if there have been any financial inducements. The league has also made it clear that, while the clubs are describing it as an amnesty, there would still be a full investigation if the authorities received any official complaints. Part of the frustration is that many clubs complain between themselves but it is rare for one to follow it up in an official capacity.