In that very great film Raging Bull there is an appalling scene in which Robert De Niro playing Jake LaMotta succumbs to despair and bangs his head repeatedly off the wall of his prison cell. It’s based on a true incident as recounted by LaMotta and incidentally helped De Niro win his second best actor Oscar.

It made a powerful impression on me back in 1980 and I think about it occasionally. Sometimes I think I have been banging my head off the wall for years with my repeated warnings about the sheer dangers of modern rugby, due to the sheer size and strength of contemporary players.

I know my fears are shared by many people in the rugby community, but there has been a general silence, mostly because nobody wants to rock the boat in the professional era when money talks louder than even health and safety.

Imagine my surprise and a delight at the weekend when some of the most respected people in the sport of rugby union sounded nothing less than a clarion call to World Rugby and all the unions over their deep concerns about the safety of the modern professional game.

In case you missed it, five genuine rugby ‘greats’ – Sir Ian McGeechan, Willie John McBride, Gareth Edwards, Barry John and John Taylor – got together and penned a letter to Sir Bill Beaumont, chairman of World Rugby, saying the game had become “unnecessarily dangerous”. They were joined by consultant surgeon Professor John Fairclough.

The letter quoted former Wales captain Sam Warburton who said two years ago that someone "will die during a game in front of TV cameras" if nothing is done. Worryingly the famous five asserted that people in the game were afraid to speak out for fear of losing their livelihood.

The key lines in their letter were these: “Rugby union was conceived as a 15-a-side game for 30 players. With the current eight substitutes per side, many of whom are tactical 'impact players' or 'finishers', this can and often does stretch to 46. 

“More than half a team can be changed, and some players are not expected to last 80 minutes so train accordingly, prioritising power over aerobic capacity. This shapes the entire game, leading to more collisions and in the latter stages numerous fresh 'giants' crashing into tiring opponents.

"The simple change we advocate is to allow eight subs on the bench if you must, but limit the number that can be used to four and then only in the case of injury.

"This will make the game safer, a view supported by leading players and eminent members of the medical profession."

What a simple but brilliant idea. In a sense, we would be going back to the situation that pertained 25 years ago. Back then replacements were actually genuine substitutions with only injured players being replaced.

Tactical substitutions arrived on the scene just months after Rugby Union permitted professionalism in 1995, and it was no coincidence, because the more players allowed on the pitch, the more people got paid.

It used to be in football that bonuses were only paid to those who had actually taken part in the match, and many a manager would stick on a late substitute so that the player could get a bonus. Covering a lower league game, I once heard the club chairman berating a coach for sending on a substitute to replace a player who wasn’t injured. He was speaking out of his wallet, of course, but maybe that chairman had the rights of it.

The situation has utterly transformed since 1996, and I feel it will be very difficult for world rugby to turn back the clock as demanded by the five. I wish them all the very best, but cynic that I am I cannot see World Rugby making the necessary changes, at least not without a committee or panel being set up to talk about if for umpteen years. I would love to be proven wrong, but I hae ma doots.

I wrote not too long ago that rugby has become a 23-man game, and wholesale changes of personnel and tactics during a match have become the norm rather than the exception. Indeed some coaches such as South Africa’s Rassie Erasmus with his bomb squad off the bench have made a reputation on the way they use replacements.

That must change. This warning must be heeded, not least because those involved in rugby administration know that there are injury-related court cases lining up which could cause rugby very dear. Sadly they are necessary to force the unions and World Rugby to confront past complacency and face the fact that, as Sam Warburton said, we could see death on the pitch.
I hope and pray it will never be so, and changing the laws on replacements will help avoid such a tragedy.