THERE USED TO BE A SAYING IN FOOTBALL THAT IF YOU EVER MET A GIRL WHO COULD EXPLAIN THE OFFSIDE RULE, YOU SHOULD MARRY HER STRAIGHT AWAY.

These days, I’d be happy just to meet a referee who could outline, clearly and without ambiguity, what the latest interpretation should be of the game’s most controversial ruling, Law 11: Offside.

Offside is judged from the moment the ball is played, the main exemptions being when the attacking player receives the ball directly from a goal kick, corner or throw-in. A player used to be in an offside position if he was nearer to the opponents’ goal line than the ball, unless there were at least two opponents ahead of him – generally the goalkeeper and one defender – or he was in his own half or he was not involved in active play.

In 1990, it was decided that an attacking player can be level with the second last defender and still be declared onside, which is supposedly easier to see with the human eye. But the area that has needed most clarification is when an attacking player is deemed to be “in the opinion of the referee, involved in active play”, more commonly referred to as “interfering with play”.

Bill Shankly’s canny take on the offside rule was that if one of his Liverpool players wasn’t interfering with play or seeking to gain an advantage, then he shouldn’t be on the pitch. So how do referees make their judgments?

In September, 2003, the International Football Association Board announced a decision to clarify Law 11 – not change it – to “ensure uniform interpretation” of the offside ruling.

The law itself states: “A player in an offside position is only penalised if, at the moment the ball is touched or played by one of his team, he is, in the opinion of the referee, involved in active play by:  interfering with play, or interfering with an opponent, or gaining an advantage by being in that position.”

The Board qualified those phrases as follows. “Interfering with play,” means playing or touching a ball passed or touched by a teammate while occupying an offside position. Clear enough.

“Interfering with an opponent,” includes preventing an opponent from playing the ball, or obstructing the goalkeeper’s line of vision or movements or making a gesture “while standing in the path of the ball” to deceive or distract an opponent. Not easy to spot with everything else going on.

“Gaining an advantage by being in that position,” refers to playing a ball that rebounds off a post, the crossbar or an opponent, having been in an offside position.

When Patrick Kluivert scored for Newcastle in the 3-1 defeat at Liverpool last month, he was stood a good couple of yards “offside” as a defence-splitting pass released teammate Lee Bowyer. Referee Graham Poll decided that, at this stage of the move, Kluivert wasn’t actively involved. However, Bowyer then cut the ball back to Kluivert, who, having continued his run, tapped the ball home from close range. Here was a player who was apparently offside yet allowed to score a goal within the same attacking period of play.

A week later, Middlesbrough thought they had taken the lead at Birmingham. Jimmy Floyd Hasselbaink fired in a shot at goal from the edge of the penalty area which deflected off the toe of Birmingham’s Stan Lazaridis and into the goal. As this happened, there were three Middlesbrough players whose runs had taken them into offside positions, but they were not blocking the goalkeeper’s view, had done nothing to distract Lazaridis or Maik Taylor in goal and had certainly not touched the ball or played any part in the move. Referee Steve Bennett disallowed the goal and Middlesbrough went on to lose 2-0.

“I simply cannot find an explanation as to why that goal was ruled out,” said Boro manager Steve McClaren, while Steve Bruce, the Birmingham manager, started inventing his own terms. “It’s a grey area alright,” he said, “but in my book, if you’ve got someone standing in the six-yard box in an offside position, then he has got to be offside.”

Not according to the rules he hasn’t Steve. The only clear-cut thing you can say about the offside rule is something my fiancée pointed out to me as I yelled at the television the other day . . . “The referee’s decision is final.”