Collingwood fans could never be accused of failing to express their emotions when feeling aggrieved.

For better or for worse, that's a tradition that has stretched back 121 years.

Mostly, it has taken the form of what the black and white army did so vocally last Saturday night when they sent off the umpires with a cacophony of boos because of the lop-sided free-kick count, despite the Magpies' upset win over the Cats.

But on occasions, this expression of frustration at the men in white (or whatever colour they are wearing nowadays) or the opposition side has gone too far, pushing beyond what was considered fair or reasonable behaviour.

A club cannot deny its own history, even the less attractive aspects. But importantly it can learn from them. And, for the most part, Collingwood has.

Fortunately, the instances of those more extreme reactions have become rarer in recent years, and that’s had as much to do with the change in community standards as anything else.

There have been times, though, when some Collingwood barrackers have crossed the line, particularly in the early years.

The attitude to umpires wasn't always a negative. In one instance, in 1896, Collingwood's stout (and undoubtedly stout-hearted) defender Bill Proudfoot stepped forward to protect an umpire after a match against North Melbourne at Arden Street. Proudfoot succeeded, even when his safety was put in peril, and the umpire was able to make a hasty getaway from trouble.

But Collingwood fans haven't always been as helpful or as accommodating to umpires.

One of those occasions came 90 years after Proudfoot "saved" the man in white from harm.

In this particular match, against Sydney in Round 13, 1986, a small section of the Victoria Park crowd became so enraged by the way in which the game finished, that they rushed onto the field, threatening the safety of the umpires.

What transpired in fading light on that June 21 afternoon made negative headlines in Melbourne.

A free kick to Swan Barry Mitchell - which video would suggest was the correct one - ended with the match-winning goal in a controversial finish. It sparked a response that no one at Collingwood was proud of, as the moment threatened to slide out of control.

For much of the day, this looked like just any other match at the Magpies' home ground, one that the home side appeared to have in their grasp for the best part of three quarters.

Few people had given the Swans any change of upsetting the Magpies that day, who were shooting for a fifth successive win in Leigh Matthews' first season as coach.

Matthews had taken over from Bob Rose, who had resigned after three losses to start the season, and he set about trying to re-invigorate a club that was in financial and football trouble.

This was to be Matthews' 10th match as coach; and the man he was squaring off against in the coach's box was Tom Hafey, in his 464th game as coach. Hafey was no stranger to Victoria Park, given he had coached the Magpies for five and a half seasons and into five Grand Finals.

Collingwood legend and Sun Kiss of Death columnist Lou Richards was one who could not foresee just what sort of competition the Swans were going to bring to the contest.

On the morning of the match, he used his well-read but often wildly exaggerated column in the Sun News-Pictorial to provide Hafey and the Sydney players with plenty of ammunition.

Richards wrote: "Sydney Swans? Don't make me laugh. They will be known as the "Wimps of Woolloomooloo" after Collingwood gets through with them at Victoria Park today."

He suggested that the "blinding skills of Peter Daicos, Shane Morwood, Bruce Abernethy and Darren Millane" would lead to a one-sided contest, with forwards Brian Taylor and David Cloke providing plenty of action in attack.

The team had a mix of experienced players and youngsters coming through the ranks. The side had four members who had played more than 100 games - Cloke (241), Tony Shaw (162), captain Mark Williams (127) and Peter Daicos (124).

Wes Fellowes, playing his 70th game, was on his way to winning an unlikely Copeland Trophy that season.

Eight of the 20 players against the Swans that day would become premiership players four years later - Shaw, Daicos, Denis Banks (92nd game), Michael Gayfer (13th game), Shane Kerrison (9th game), Darren Millane (36th game), Shane Morwood (82nd game) and Jamie Turner (27th game).

Three players had played fewer than 20 games - Kerrison, Darren Handley (fourth game) and Dannie Seow (seventh).

Richards' pre-game optimism seemed well-guided for much of the first three quarters.

Early in the third term, Collingwood had extended its lead to a seemingly impregnable 34 points. The Swans hit back with four goals to three in the third term to make the three-quarter-time margin 18 points.

When Daicos, on his way to a 24-touch performance that saw him his team's best player, kicked his second goal of the game early in the last term, the difference was back out to 24 points.

It would be the last time the Magpie faithful would cheer that afternoon as light began to fade.

But Sydney was far from done with.

As the Herald wrote: "You could see it happening as if the Swans were a huge bonfire on a ground not noted for pleasantries in tight finishes.

"A goal to (Warwick) Capper then to (David) Murphy and then (Barry) Mitchell. A behind to Capper and another to Mitchell. Collingwood led by only five points and the (final) siren was just 10 minutes away. Then it happened ..."

It was a contest between Barry Mitchell, who would later end up at Collingwood for a brief and unsuccessful time, and Shane Kerrison.

Kerrison attempted to tackle Mitchell, but the umpire deemed it a push in the back, although the Herald suggested: "A wild element in the Collingwood crowd maintained that Mitchell had held the ball."

Mitchell took advantage of his free kick to boot the final goal of the game, putting the Swans in front. It was followed by a behind to Collingwood's Mark Williams, which levelled the scores, before Murphy edged the Swans in front with a point.

And the anger was about unfold even further when the timekeepers pushed the final siren.

The Herald recorded: "Everything boiled over at once. The umpires were now the main target in the eyes of those who know nothing about football or how to conduct themselves in a public place."

Angered fans screamed that Collingwood had been robbed of a win.

As the umpires Shane McDonald and Peter Howe headed towards what should have been the sanctity of the umpires rooms, a gathering of supporters "surged forward" and "pushed two police horses together, leaving the field umpires in front of them and the boundary umpires behind."

The Sun reported: "A man ran up to Shane McDonald, 23, and spat in his face. the man was pulled away by ground staff but broke clear to strike umpire Peter Howe, 29, with a stiff arm blow to the head."

"Hundreds of spectators heckled the umpires as they came off the ground and some of the crowd threw cans at the men in white,. One spectator attacked Swans wingman Merv Neagle seconds after the game and his teammates Jim Edmond ran in to stop what could have developed into a brawl."

Sgt Wayne Miller called it: "One of the ugliest incidents we have seen. They (the crowd) were certainly fired up."

Lou Richards said: "In the old days Magpie fans used to shout: ‘Kill the umpire.’ Nowadays some ratbags try to do it. Fair dinkum, the club and the sport need those sort of supporters like I do a boil on the backside."

And the police were keen to lance the boil, as they carried out video analysis to try and find the perpetrators.

The Sun's chief football reporter, Peter Simunovich, himself a Collingwood fan, was also grappled by supporters near the umpires and visiting team's dressing rooms. He watched the Mitchell free kick over and over and concluded it was correct.

In the aftermath, Victoria's Minister for Sport and Recreation, Neil Trezise, who had played at Victoria Park eight times when he was a Geelong player, foreshadowed there might come a time when wire fences might one day be needed to separate the footballers and the public, as had been the case in sporting codes overseas.

Premier John Cain quickly scotched the suggestion and gave a strong vindication of the great majority of Collingwood supporters, saying they were a strong part of the fabric of the game.

And other than the embarrassment to the Collingwood Football Club, there was no lasting ramifications arising from that strange day at Victoria Park in 1986.

President Allan McAlister urged fans in the aftermath that they need to be respectful to umpires and to the club itself.

"We certainly don’t want to see anything like that happen again," McAlister said. "We believe that type of behaviour is detrimental to the game and Collingwood."

It had been detrimental, but with a general change in community standards coming over the past generation,  there has been a significant shift in crowd behaviour.

And that dark, distant day from 1986 pretty much remains only in the memory of those who were there.