‘I would say that football in England is beautiful thanks to Jean-Marc Bosman.” So says the former Belgian midfielder who arguably had more of an impact on the European game than Cristiano Ronaldo and Lionel Messi combined. Now he “earns nothing”, has two children to raise and is remembered by many as a mere name in history. Bosman. On a Bosman. A Bosman deal. He is often forgotten, perhaps because 20 years after his landmark victory at the European Court of Justice, it seems difficult to recall a time when elite players ever felt seriously trapped.

“I was held captive at my club,” remembers Bosman, 51, of his life’s turning point in 1990. “I was at the end of my contract with Liège. They offered me a new contract worth four times less than the previous one, and to sell me to Dunkirk they were demanding four times the price at which they had bought me. In other words, they thought that I had become four times better if I wanted to leave and four times worse if I wanted to sign again for them.

“I didn’t accept this procedure, which I considered to be completely illegal. I was suspended by the Belgian federation because I didn’t want to sign. But if I didn’t re-sign I still belonged to Liège and I didn’t accept this. I missed an opportunity to earn much more money at another club.”

Before 15 December 1995 the football landscape in Europe was incomparable to today. It was a different era, only three years after the formation of the Premier League and with TV subscriptions yet to hit the boom times. There were quotas on the number of foreign players an English team could field in a Champions League match. Uefa regulations permitted up to three in any team, with two “assimilated” members who had progressed through a club’s youth set-up. In 1994 the restrictions meant Alex Ferguson replaced Peter Schmeichel in goal with Gary Walsh, and Manchester United lost 4-0 to Barcelona.

Before 1995 an out-of-contract player could not simply leave a club. A free transfer had to be granted or another club’s fee accepted. A player could not run down a contract to depart for nothing, and certainly not sign a pre-contract agreement with a rival if they had less than six months remaining on an existing deal.

The idea that an in-demand player with one year remaining on a contract held all the cards was anathema. The possibility that a multimillion pound star could leave for nothing was fanciful.

Jean-Marc Bosman training in 1996. Photograph: Jose Manuel Ribeiro / Reuters/Reuters

In 1990 Bosman was suspended by Liège. Six months later he left for a short spell at the French club St Quentin, but after that no one would touch him. He sued Liège, the Belgian FA and Uefa for breaching the 1957 Treaty of Rome allowing freedom of movement within the European Community, now the European Union. “The message had been given by Uefa and Fifa to all clubs not to hire me because I had taken legal action against Uefa, Fifa, the Belgian federation and Liège,” Bosman says.

“At that point I realised that my career was going to end so I decided to take action against the nationality clauses. My reasoning was that I was a European citizen and I should be able to move as freely as other workers.”

His victory in Luxembourg was undoubtedly a turning point. For some, power has since swung too radically from clubs to players – and therefore agents – while at the time the court’s ruling had many within the game concerned about the future. The foreign quota may have benefited those playing in Europe but English clubs feared a significant cultural shift.

Players could demand increased wages when moving on a free transfer. Signing-on fees became prevalent, with the richest clubs seemingly strengthening their grip at the summit as others failed to keep pace with the inflating costs. Post-1995, some clubs who fell into financial difficulty had to sell players at vastly reduced prices having originally signed them on long-term contracts.

Daniel Geey, a sports law expert and partner at Sheridans, says: “Bosman is still seen by the legal community as one of the most important EU sports law cases of all time.

“The reach and consequences were so large because clubs and players saw the European courts siding with a player on a matter of EU law against one of the established sporting institutions. But the lower you go down the leagues, the precarious nature of being out of contract is a difficult situation to remedy.

“League One and League Two players, for example, will not see entering the last six to 12 months of their contract as a positive impact. Being out of contract has significant downsides. Bosman had a huge impact on club spending on players, but in the same way lots of money flowed in from a variety of commercial sources.”

On the unintended negative effects, Bosman says: “The upshot is that now the 25 or so richest clubs transfer players for astronomical sums and smaller clubs cannot afford to buy at those prices. So the 25 pull further and further away from the rest, deepening the gap between big and small. That was not the aim of the Bosman ruling, it was caused by what Uefa and the clubs did afterwards.”

Steve McManaman was one of the early players to benefit from the ruling, moving to Real Madrid from Liverpool in 1999. There have been numerous others since then, including Sol Campbell, Andrea Pirlo, Michael Ballack and, more recently, Robert Lewandowski.

Fifpro, the world players’ union, has supported Bosman and is still fighting to improve global transfer rules. In 2001 Fifa, Uefa and the EU established transfer regulations that provided some exemptions from European law, but Fifpro wants further changes regarding unfulfilled pay and contract terminations.

For Bosman, however, there has been little benefit. The fight cost him financially and mentally. But he says it was for the greater good. “I think I did something very good. I gave people rights. Now I think there may be a new generation of players who don’t realise how lucky they are to be able to leave a club and join another, even if they are the fifth or sixth foreigner there.

“I think there are players who earn a great living – good for them. There are some who earn 300k per week, others earn less, but in England there are a lot who earn a fine living. Me, on the other hand, I earn nothing now. Now I’ve turned the page on everything that happened. Because in the past I got a lot of promises but never received anything.

“I am proud of the ruling because people will still be talking about it in years to come, maybe even after I am gone in 20 or 30 years or whatever. Maybe they will think they should at least thank me, nothing more.”