THE soccer trade system was revolutionised in 1995 when Belgium player Jean Marc Bosman went to the European Court of Justice and won the right for players to move freely to another European club of their choice when out of contract.

Until then, players were tied to their club, even when out of contract, unless the club agreed to terminate their contracts.

Clubs would do this only if another club made a deal — usually financially — to trade the player.

The system now exists where players are tied to their club during their contracts unless a rival club makes an offer that is acceptable to the selling club, which then terminates the contract and registration allowing the player to switch.

If the offer is unacceptable, then — in theory — the club will refuse and the player must remain at the club. In practice, players will often pull a variety of stunts including faking injury, or just downright childish refusal to play in order to secure a transfer.

If a player is out of contract, he is allowed to move for free on what has become known as a "Bosman". A player is allowed to start negotiating with other clubs as soon as he enters the final six months of his contract.

A transfer can be completed only in either of two transfer windows, or trade periods. The main summer window runs from the beginning of June until the end of August 3. The winter transfer window opens for the whole of January.

At the top levels of the game, the consequences have resulted in power transferring from the clubs to the players (or more often their agents). Once a player enters the later stages of his contract, his transfer value falls rapidly as he gets closer to the stage when he can move for free.

Clubs must either sign players on long-term deals and try to renegotiate a contract two years before it ends, or sell mid-contract in order to get as much money as possible.

Either way, the player wins … at least financially he does. He will either get a new contract with improved terms or he will switch clubs and receive a new contract as well as a fat signing-on fee.

The result is that — with no salary cap — players' wages have gone through the roof because while clubs might save money because there is no transfer fee, the player will then demand a payment to sign on top of the inflated wages he already commands.

At the lower levels of the game, transfer fees have practically disappeared as clubs no longer splash out their limited funds on mediocre players when they can pick up an equivalent for free on a Bosman.

In order to protect smaller clubs who develop their own talent, the rules state that a transfer fee much be negotiated for any player under 23. If a fee cannot be agreed, then a tribunal decides the appropriate compensation.