Mike Flanagan, George Best and Trevor Francis are three players who have distinguished themselves in the North American Soccer League, and who have caused great commotion in the process.

Flanagan, most valuable player last year in the NASL, caused one English sports columnist to write: "American soccer is show business run like big business by owners who reckon they have the right to lure any player not actually nailed down . . . The moral? There must be no more 'understandings' across the Atlantic. The Americans are now so rich, and our clubs and players so avaricious, the English League should insist no Briton crosses the pond until they've seen and approved every detail of every deal."

To briefly sum up the three cases, Flanagan has been on strike because Charlton Athletic, his south-east London club, has refused to let him go back to the New England Tea Men. Francis, England's first million-pound player, is in trouble with the English Football League because his new club, Nottingham Forest, allowed him to fly to Detroit in midweek and scored six goals in an exhibition game against the Cosmos. Best has been allowed by the world governing body, FIFA, to resume playing for Fort Lauderdale, only days after his English club, Fulham, obtained a decision in the English High Court denying him permission to do so.

Flanagan's is the most contentious, controversial affair of the three. It has had a displeasing aroma about it from the very first, when Charlton, a year ago, gave him permission to play for the Tea Men on loan as part of the deal that linked the two clubs on what should have been a fraternal basis.

Charlton's fans, with good reason, were incensed. The club was in grave danger of being relegated from the Second to the Third Division, and to allow its leading goal scorer to skip away and make money in the States weeks before the English League season was over seemed intolerable. In the even, Charlton escaped by the width of a goal post, the goal post the forwards hit when the clubs played an all-London game at Leyton. But the Charlton fans have neither forgotten nor forgiven.

The football league, usually so draconian when it comes to intervening in such matters, especially when they concern the NASL, inexplicably stood by like Pontius Pilate. The threat to the reality of English League competition was plain. Had Charlton been dropped a division, it would have been precisely because Flanagan was in Massachusetts, not London.

No more than a good second-rank player in England, Flanagan blossomed in the U.S., where, in the process, he is estimated to have pocketed $70,000 for the summer. That probably is three times as much as he would have made all season in England, even if Sports Illustrated did list him as an underpaid athlete.

Charlton let him go, as Birmingham City let Francis go to earn $100,000 in Detroit, as a means of keeping him. It didn't work with Francis, who is now with Nottingham Forest, and it hasn't worked with Flanagan.

A few months ago, the Tea Men tried to extend their use of Flanagan for the present NASL season. Charlton, which, it seems, had at first agreed to that, now will not let him go. A legal technicality guaranteed their position; NASL rules, ironically, proved them right, though the morality of the affair was another matter.

You could hardly blame the Tea Men for being furious. In the meantime, the Tampa Bay Rowdies came after Flanagan, offering a very large transfer fee. Flanagan made it clear he did not want to join the Rowdies but preferred to return to the Tea Men as, he insisted, Charlton had promised him he could. Matters were complicated by a brawl on the field with the notorious Derek (Killer) Hales, a forward who, much to Flanagan's dismay, had been bought back by the club from West Ham United after a spell with Derby County.

Flanagan and Hales detest each other, and the auguries were grim when Flanagan's remarks in America, off the record, were picked up and published by an English newspaper. Hales, a player with a record of violence, made threats and ultimately struck Flanagan in the course of a game at Charlton.

The club handled the whole matter with incredible ineptitude, first canceling Hales' contract although retaining his registration as a player-which meant he couldn't go eslewhere - then changing its mind and reinstating him.

Flanagam, having first said he was "withdrawing his labor" because he wanted to go back to Massachusetts, then explained that the real reason was the fact that Hales had been restored to favor. No one in London took that very seriously. The Tea Men threatened Charlton with legal action, Flanagan continued to stay away, and no one came out of the affair with credit.

Nor do they in the case of Best. The English League never did like the deal whereby Fulham was to share him with the Los Angeles Aztecs. Last NASL season, the Aztecs, to Fulham's rage, sold Best to Fort Lauderdale. Fulham managed to get him banned by FIFA, which suddenly changed its mind the other day on the grounds that Fulham didn't want Best for itself but merely wanted to be paid for his transfer. This time, it was a case of a decision that might have made sense in moral terms, but was ludicrious in law.

Then there's Francis, a player notoriously injury prone, who nevertheless has condemned himself to playing football 12 months a year. When Nottingham Forest signed him from Birmingham and gave him permission to play summer football in America, there was a violent reaction. Bill McGarry, coach of the Newcastle United clubs, accused them of selling the pass, and he was right. Moreover, the rules of the European Union demand that Francis be back in England by Aug. 4 or he won't be eligible for any European Cup competition until the quarterfinals.

Clearly, things are on a collision course, and the collision cannot be long delayed.