By Phil McNulty
Chief football writer
English clubs took the brunt of the punishment inflicted by Uefa after the 1985 European Cup final between Liverpool and Juventus in Brussels.
The Heysel Stadium was the scene of fatalities in 1985
A wall collapsed at the dilapidated Heysel Stadium as Juventus supporters attempted to escape crowd trouble that erupted prior to kick-off on 29 May.
The Belgian authorities had allocated a section of the ground to neutral fans, an idea opposed by Liverpool and Juventus because it could provide an area for fans of both clubs to obtain tickets from touts outside the ground and evade segregation measures.
A flimsy wire fence was erected in an attempt to segregate Liverpool fans from the neutral area.
But when a contingent of Liverpool fans began to stampede towards the Juventus fans - many claimed it was a response to the act of throwing rocks and other missiles by Juventus fans - a retaining wall collapsed.
The tragedy claimed 39 lives (38 of whom were Italian) although the game went ahead and Juventus won 1-0 win after Michel Platini's penalty.
Liverpool condemned the violence, but the late Sir John Smith, chairman of the club at the time, said: "The ground was not good enough for an ordinary match, let alone a final."
Prime Minister Margaret Thatcher, outraged by the behaviour of Liverpool fans, ordered the FA to withdraw English clubs from European competition.
Uefa took sanctions as early as 2 June, banning English clubs from Europe for "an indeterminate length of time."
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Watch BBC Two's Heysel documentary
Sunday 17 April 2100 BST
Fifa initially extended the sanction to a worldwide ban, including friendlies, although they swiftly moderated the punishment to allow English clubs to play friendly and exhibition matches abroad.
The ban lasted for five years, although it was six years before Liverpool returned.
Liverpool's Merseyside neighbours Everton, who shortly before had won a trouble-free European Cup Winners' Cup final against Rapid Vienna in Rotterdam, suffered as a result of the ban.
They had also claimed the league title that year, but were prevented from entering the European Cup, as they were again when they won the league again two years later.
Norwich City won the League Cup, against Sunderland at Wembley in 1985, but could not build on their success as they could not enter the Uefa Cup.
Belgium was banned from hosting a major European final for 10 years, and Uefa itself was heavily-criticised for allowing the game to be played at Heysel, a run-down location.
Heysel Stadium has been rebuilt and renamed
Uefa and the Belgian authorities came under fire for the arrangements, with former Liverpool chief executive Peter Robinson expressing fears about opposing supporters being placed in the same end of the stadium.
Liverpool's reservations proved well-founded as rioting ensued in the stadium, with only that flimsy fencing separating supporters in the infamous Block Z.
Uefa has since imposed stricter regulations on stadium security, with new ticketing procedures.
Tickets on sale in Belgium for the Liverpool end also allegedly fell into the hands of Italian immigrants, which heightened the potential for trouble.
The aftermath of Heysel was dogged by claim and counter-claim about supporters entering the ground without tickets, and that even those with tickets were not subjected to inspection.
The match went ahead, a decision most believe was correct irrespective of the tragedy, on the basis that to abandon it and play it again could have sparked further hooliganism.
Former Uefa chief executive Gerhard Aigner, who was head of the competitions department in 1985, said: "The police said they couldn't evacuate the stadium, so they were more or less forced to play. That was when we were asked to go out and speak to the teams."
Aigner recalls how one part of the police force at the match was the national gendarmerie and the other was Brussels police - a fatal split.
The two sections did not have a joint command, with Aigner revealing: "This proved to be catastrophic. They didn't have enough police in the stadium and some police did not have batteries in their walkie-talkies."
The disaster led to increased vigilance from Uefa, who had to take their share of responsibility for the shambolic scenes that unfolded in Belgium on that hot May night.
All Uefa's big matches now have strict ticketing procedures, safety is paramount and stadia are equipped with closed-circuit television and greater communications inside the grounds.
The Heysel Stadium itself has been completely renovated and renamed as the Roi Baudouin stadium and successfully staged matches at Euro 2000.
And 20 years on, Liverpool and Juventus prepare to meet again.