Thus any restrictions placed on their right to work (such as quotas setting maximum numbers of such foreign players in sports teams) are deemed illegal under EU law.

At that time, Slovakia was not yet a member of the European Union (it joined the EU in May 2004), and therefore the Bosman ruling did not apply to its citizens.

Such countries include those within the African, Caribbean and Pacific (ACP) group of states, such as South Africa, Jamaica and Zimbabwe.

[3] Because that was classed as a way of encouraging counties to develop young players who could go on to play for England, rather than a restrictive quota system, it was legal under the EU rules.

[5] The influx reached a peak in 2008 when, during a match between Northamptonshire and Leicestershire, half the players on the field were from non-EU countries.

The Home Office was subsequently able to introduce new rules placing restrictions on Kolpak players, stating that only those who had held a valid work permit for four years had the right to be treated the same as EU citizens.

In a related issue, New Zealand player Andrew Mehrtens, who was born in Durban, decided to pursue a South African passport when he signed with the English side Harlequins for the 2005–06 National Division One season, as it would enable the club to sign another non-EU and non-Kolpak player.