Maros Kolpak: has had a bigger effect on English county cricket than any single person since Lord Hawke © Getty Images
The Kolpak ruling was handed down by the European Court of Justice on May 8, 2003. Maros Kolpak, a Slovakian handball player, was released from his German club because of a quota on non-European Union players, imposed by the Deutscher Handballbund (German Handball Federation). He claimed this was unfair and the case went all the way to the European Court which ruled in his favour.

The court reiterated the pre-existing Bosman ruling (which has had such an effect on football), and declared that no resident of the European Union should be prevented from working in another part of the EU. The net effect on cricket, if that had been the end of the saga, would have been minimal because the sport is hardly prevalent on mainland Europe.

But - and this is the important part - at the time of the ruling Kolpak was not from the EU but from a country with an associate trading relationship. So the Court of Justice's findings meant that any player from any nation which had such a relationship with the EU could also freely play as a professional.

The main cricket-playing countries with associate trading relationships with the EU include South Africa, Zimbabwe and several in the Caribbean, and the county game has seen an influx of cricketers, especially from South Africa, under the Kolpak ruling since 2004.

Critics point out that Kolpak players are not qualified for England, and so fear that the county game will be inundated. But as the man himself told Wisden in 2005, he was not thinking of Leicestershire or Northamptonshire when he went to court. "I did it for myself," he said.

Initially, the ECB said that no Kolpak player could have represented his own country in the previous 12 months, but that was found to be unenforcable when Yorkshire signed Jacques Rudolph early in 2007.

The board now offers a financial incentive to counties whereby every game that a side fields a Kolpak player they get £1100 deducted from their annual central handout.

Martin Williamson is executive editor of Cricinfo