As part of their efforts to raise refereeing standards, the Professional Game Match Officials Limited monitor the performance of the men in black at every game played in The Football League and Premier League. Here, we offer an insight into how the process works.

With so much at stake in the Play-Off semi-final second legs, spare a thought for the match officials who have to operate amidst all the sound and fury knowing potential controversy is never far away. Running the rule over Referee Mark Clattenburg and his assistants at the City Ground as Nottingham Forest took on Blackpool was Assessor Kelvin Morton and The Times' Russell Kempson was granted rare access to sit alongside him. Here is his fly-on-the wall report.

Kelvin Morton has had a good drive to the City Ground from his home in Bury St Edmunds, Suffolk, aided by TomTom, his constant companion.

"I like to arrive at the ground two hours before the game," he muses. "But I always allow a bit of extra time, just in case of the traffic. You never know."

He arrives in the Garibaldi Room, a small suite in which rival managers seeking a sneak preview of their next opponents or prospective purchases, club scouts and guests gather. And the match officials and their assessor. The room is almost deserted apart from a tray of sandwiches, marked "Referee and Assistants", in the middle of a large table.

Kelvin considers a stealthy raid but resists the urge. He reminisces with the tea lady about the good old days, when Brian Clough ruled with an iron fist and when Morton, a leading Referee, strutted his stuff in the middle.

"It's nice to turn back the clock sometimes," he reflects. But before he grows misty eyed, Mark Clattenburg, his assistants, Mike McDonough and Stephen Child, and Lee Mason, the Fourth Official, arrive. A quick chat and, 15 minutes later, they leave. Down to business.

Morton, 64, still enviously eyes the sandwiches but, soon, it is down to business for him, too. A briefing with the head of ground security and the chief police commander. An hour before kick-off, Kelvin trots off to see the captains - Paul McKenna, of Forest, and Charlie Adam, of Blackpool. Clattenburg has a word with both, telling them what he expects and that he wants no silly bookings. Teamsheets are handed in, the expectation mounts.

Ten minutes before the off, Morton takes his place in the directors' box. On the right of the stairs, second row, first seat in. Prime position to judge Mark, Mike, Stephen and Lee. Little can escape Morton's attention and little does. "It's a great atmosphere," he says, stopwatch dangling from his neck and clipboard on his lap.

Clattenburg blasts his first whistle. Game on. "Ask me what you want," Kelvin says. "But I might be making notes. And you won't be able to read my writing. It's like a doctor's!" It is. By half-time, a spider dipped in ink appears to have crawled across his two sheets of paper. "They're my crime sheets," he says. "What I call submissable evidence."

Over the years, since he retired from refereeing in 1995, he has devised his own note-taking strategy - Assessing Made Easy. Columns for strengths, room for improvement, incidents, bookings, errors, free kicks. He divides the pitch into nine segments for simple identification.

As the game progresses, Clattenburg appears to be racking up an impressive amount of mentions in the "strengths" section. "But I look at all four of them," Morton explains. "How they work as a team. That's important."

Forest are leading 1-0, all is fairly quiet in the world of officialdom until, in first-half stoppage time, Child flags for offside against Forest. "Just off,'' Morton murmurs. Child's play, clearly.

David "Ned" Kelly, Forest's Assistant Manager, does not agree and exchanges views with Ian Holloway, the Blackpool Manager. Mason intervenes and gets a finger-jabbing from Billy Davies, the Forest boss. Calm is restored as Clattenburg signals the interval.

Taking refreshment in the Garibaldi, Morton is suddenly aghast. "Yeah, as I was saying, it was just offside ... oh dear." He glances at the television replay and notices, as does everyone, that the ruling should have been, er, onside! "It goes to show how difficult these judgements are and the benefit should have been given to the attacker."

One minute into the second half, it is McDonough's turn in the spotlight. Robert Earnshaw races through to score for Forest but Mike's flag is raised. "Too slow, too slow," Kelvin mutters. Not Earnshaw but McDonough's decision-making. He should have been quicker, even by a fraction, on the draw.

From then on, Forest are felled and as the Blackpool goals rain in, the home technical area becomes more crowded and agitated. "Only two can stand in it and only one at the front," Kelvin observes.

"They've got four in there." Mason stands motionless, arms crossed. Morton makes a note.

As Forest collapse farther, Davies retreats into his dug-out. Game over, Blackpool are on their way to Wembley - the Tangerine Dream - while back at Garibaldi HQ, Morton, a General Manager with a power supply company, analyses his officials' performances. No need to refer to the spider's crawl, either, his memory is perfect.

"Mark had an outstanding command of the game from the outset. He took no risks with match control and worked extremely hard in his man-management of the players.

"The assistants did very well overall. As we now know, there was an offside given just on half-time that we thought was a good call. I know it was tight and, in fact, it was proven to be level. Onside. It was one of those difficult ones.

"Early in the second half, Mike had a disallowed goal. Perfectly correct but I felt maybe he could have flagged slightly earlier. And Lee maybe could have been a bit more proactive in the home technical area. You don't want him to micro-manage but you want him to do a bit more than he did. But it was a good day at the office, a good team effort. The one who was most sure did the leading and the other was happy to follow. Therefore, they were at one."

The dust has settled and Morton sets off for a debriefing with the quartet in their changing-room. "When I go in, I don't sit on the fence, I give an opinion," he reveals. "I think we get more respect for that.

"I love doing this job. I refereed with a smile on my face, I was known for that, and I like a rapport with people, I like the interaction. All the guys were pleased and they were very receptive to what I had to say."

It is nearly 11pm. A fine drizzle descends from the darkness and TomTom is waiting in the car park to guide Morton home. He has to write separate reports on Messrs Clattenburg, McDonough and Child the next day and also a summary, which could take up to three hours.

Time to perhaps assess the assessor: Let's go for an "A". It would have been A+, Kelvin, but for the spider! •

Kelvin Morton explains what an assessor looks for from match officials:

"I'm what we call a guardian of standards. I'm expecting the referee and his assistants to carry out the laws of the game in a professional manner to make sure that there is good match control, allowing the game to flow but not to the detriment of control.

They must also get decisions right and work hard. Most important of all, the referee must show good and appropriate man-management skills. Sometimes, he may need to be a bit stronger and, at other times, he can just have a quiet word, which can be equally effective.

We have what we term the "Step" process. Sometimes, it is that quiet word that is needed; then there is the public rebuke. Then, if that doesn't work, it has to be a yellow card. You cannot give more than one public rebuke to the same player. I often use the phrase: it is like being savaged by a sheep! Referees are encouraged, where possible, to make effective use of the captains."