Roy Keane was the Republic of Ireland's star player heading into the 2002 World Cup, but he didn't play a minute in Japan or South Korea after a bust-up with then manager Mick McCarthy.

On this day 18 years ago, shock waves were sent around Ireland and the footballing world as the combustible Corkman's public criticism of preparations and personal vitriol prompted McCarthy to send him home.

A whirlwind week had kicked off on Tuesday 20 May when the 30-year-old Keane, who was unhappy with the squad's training base on the island of Saipan, asked to be released from the squad for personal reasons.

Colin Healy was put on standby as a replacement before the decorated Manchester United midfielder had a change of heart overnight.

The drama didn't end there though, as Keane criticised the Football Association of Ireland and the team's World Cup preparations in a no-holds barred interview, fuming at the 17-hour flight to Saipan and training conditions on the remote Pacific island.

"It's different if we came here to a top training facility," he told the Irish Times in an interview published on Thursday 23 May. "The hotel is fine, but we've come here to work. You wonder why players get injured? Well, playing on a surface like that.

"I can't imagine any other country, countries in the world who are far worse off than us, playing on something like that. I don't think it's too much to ask, just for a pitch that's even watered. It's so dangerous. It's rock hard.

"One or two of the lads have picked up injuries. I'm amazed there hasn't been more but give it time. But you know, we're the Irish team, it's a laugh and a joke. We shouldn't expect too much."

The substandard training facilities were "the tip of the iceberg" for a player who announced he would retire from international football at the end of the tournament - a decision that would be taken out of his hands.

McCarthy brought the players together in an evening meeting to air any grievances, but said it turned into "a slanging match" with the midfielder, who the manager said had called him "every expletive imaginable from c to w...".

McCarthy felt he had no alternative but to send the country's most high-profile player home, saying he could not tolerate the level of abuse being directed at him.

"I have made the right decision not only for the benefit of me, but the squad as well," the Irish boss told a press conference called that night to announce Keane's departure. "We will move on and be all right because collectively we are strong.

"He is one of the best players in the world, but he is a disruptive influence."

Mick McCarthy (R) and Niall Quinn at a press conference in Saipan to announce Keane's departure

The bombshell story threatened to derail Ireland's World Cup - their first major tournament in eight years - and even saw Taoiseach Bertie Ahern launch a bid to resolve the row, but that was not enough to change things.

The damage was done and Keane headed back to Manchester from Saipan, with the country bitterly divided over whether he or McCarthy was to blame.

"I feel great and have a clear conscience," Keane said ahead of boarding a flight to England. "I am happy to be going home to see my family, it's good to be going home.

"I have no regrets. There are more important things to worry about."

Keane later said he had been enraged by a suggestion he had exaggerated injury to miss a World Cup play-off match in Iran, but accepted that his language crossed a line. "I don't regret what I said, but at the same time I agree that Mick had to send me home."

Ireland went on to draw 1-1 with both Cameroon and eventual finalists Germany, and finished second in their group after beating Saudi Arabia 3-0 before bowing out to Spain in an excruciating last-16 penalty shootout defeat.

Keane returned to make nine more appearances for Ireland under Brian Kerr, who succeeded McCarthy as manager, and later served as assistant manager to Martin O'Neill for five years.