Alex Ferguson tirade highlights how Premier League referees have their cards marked for them

It was a measure of the force with which Sir Alex Ferguson berated the linesman Jake Collin at Old Trafford on Boxing Day that, mid-rant, the globule of chewing gum he had in his mouth was projected on to the turf, momentarily surprising the manager. By then, Ferguson had worked his way from the referee Mike Dean to fourth official Neil Swarbrick and on to Collin, the linesman who had originally flagged for Jonny Evans' own goal.

There is little doubt that Dean would have been in his rights to send Ferguson to the stands for "irresponsible behaviour", the formal term for the offence. Even if he had not been convinced that Ferguson's decision to follow him on to the pitch as the officials prepared for the second half was worthy of a red card, then both Collin and Swarbrick could have recommended the referee do so for Ferguson's public admonishment of them.

That the referee chose not to do so, or report him retrospectively, came as no surprise. There is a general disposition among the Premier League's referees not to send managers – and not just Ferguson – to the stands, not least because of the influence that those managers can have on a referee's career.

Only Dean himself knows why he did not dismiss Ferguson, but there is a series of disincentives for referees not to send off managers in the system that the referees' own administrative body, Professional Game Match Officials Limited (PGMOL), runs. In fact, in the last two Premier League seasons, only Newcastle United's Alan Pardew has been sent to the stands by a referee and in that instance, in August, he had pushed linesman Peter Kirkup – such an obvious offence that there was no other option.

Considering there have been 568 games played over the last campaign and this season, more or less at the halfway point, that seems like a remarkable statistic. But when you consider the pressures on referees, the picture becomes clearer.

From this season, the assessment of the performance of the 16 select group referees has been changed. There is no longer a former referee in the stand marking their performance. Instead, a DVD of the game is sent to an assessor, usually a former referee, who watches it the following day and marks each decision made by the officiating team (under strict instructions to do so with the commentary muted in order that he is not unduly influenced).

The other assessment is carried out by the PGMOL match delegate who is there on the day of the game to act as a go-between for the clubs and the referee but is not a former referee himself. The likes of Nick Cusack, John Duncan and Kenny Hibbert, former players and, in the case of the latter two, former managers, are among those who fulfil the role.

The match delegate also comes up with a mark, but in order to do so he gets the input of both managers, phoning them a day or so after the game to ask them to rate the referee. That rating from the manager feeds into the delegate's rating. At the end of the season, the referees are placed in a league table according to their combined overall match assessor and match delegate ratings and their end-of-season financial bonus is calculated accordingly.

This is not to suggest that consideration of his delegate mark for the game, and by extension his financial bonus, played a part in Dean's decision whether or not to send off Ferguson. Embattled though they appear to be, the nation's leading referees by and large do a fine job. But it is remarkable that managers play such a key role in the livelihoods of the very officials who run their games.

On top of that, it goes without saying that a referee can find himself effectively banned from refereeing a certain club by the decisions he makes. Mark Clattenburg did not referee an Everton game for more than five years after his part in a controversial Merseyside derby in which he sent off two Everton players, failed to give the club a late penalty and did not dismiss Liverpool's Dirk Kuyt for a two-footed challenge.

Martin Atkinson waited 10 months to referee a Manchester United game after he was in charge for a United defeat by Chelsea in March 2011. After the match Ferguson was given a five-match touchline ban by the Football Association for questioning Atkinson's integrity.

PGMOL does not deny that it allocates referees strategically, according to their history with clubs. There is a sense among referees that the tacit collusion between clubs and the referees' body does nothing to reinforce the authority of officials.

As well, there is a feeling among referees that if they open the door for retrospective action against players and managers, they will attract the hostility of that particular club. There has been a tendency for referees to fudge incidents that went unpunished in the game by claiming to have "seen" them at the time, thus ruling out any possibility of the FA being able to go back on them.

On Wednesday, Swarbrick and Collin will have seen their careers flash before their eyes. This is only Swarbrick's second season on the Premier League list and he is yet to take charge of a game at Old Trafford – naturally an ambition for any aspiring referee. Collin is a Champions League linesman who had steered clear of controversy hitherto.

Only Dean and his team know why Ferguson was not dismissed but, when you look at the repercussions for the career of a referee and his assistants when a high-profile manager is sent off at home in a big game, it is not hard to see why so many officials will think twice. And do not think for a moment that Premier League managers do not know that too.