The late, great Scotland scrum-half Morgan - who died in April this year, aged 73, after a long illness - stood on Edwards' foot as Scotland beat Wales in 1973.

It was an audacious manoeuvre by rookie Morgan, then 25, on his Scotland debut. Edwards remains arguably the greatest player to have donned a rugby jersey, but met his match that day.

Morgan's methods had a legacy beyond that year's Five Nations, though. In 1989, Robert Jones used them against Nick Farr-Jones as the Lions beat Australia.

Jones, in standing on his opponent's foot, sparked a huge brawl in a match that became known as the 'Battle of Brisbane'. And it gave the Lions the psychological advantage they needed to help them take the victory.

The tourists were led by outstanding flanker Finlay Calder, but it was another Scotsman who provided the vital link of experienced guidance to Welshman Jones.

Ian McGeechan had been at centre in that 10-9 Scotland win over Wales at Murrayfield in 1973 - and was to enhance his credentials as a world class coach on the 1989 tour to Australia.

The scene had been set the week before the infamous match in Brisbane, as Australia, with their captain and scrum-half Farr-Jones to the fore as the hosts comfortably saw off the Lions in the first Test.

McGeechan dropped a host of his first-Test starters and loaded the pack in particular with physically imposing players such as England locks Wade Dooley and Paul Ackford and number eight Dean Richards.

At 5ft 8in and a little over 11st, Robert Jones was the most diminutive of the Lions' line-up.

But Jones, with McGeechan in his ear in the build-up, was the catalyst for the moment in which the Lions took control of the series.

"The first Test, we'd been blown away really by an Australian side who were head and shoulders above us on that particular day," Jones told BBC Radio Wales' Sunday Morning with Scott Quinnell & Co.

"Their captain and biggest influence was Nick Farr-Jones. He was outstanding in terms of his leadership and ability to get the best out of that team.

"So Ian McGeechan, who is a great coach and great rugby man with great knowledge of the game, almost immediately afterwards got me to think about how in the next Test, which, we had to win, we could knock him off his game and ultimately probably make sure that he didn't have the influence that he had in that first Test.

"Throughout the week, he just kept at me all the time, kept getting under my skin. When the side was selected, we brought in a lot of the English cavalry in terms of size and physicality up front.

"When we got to the ground, I knew I had to do something to knock this great player off his game, which would allow us potentially to win that game and hopefully the Test series.

Robert Jones joins Jeremy Guscott in celebrating the Lions centre's winning try in the Lions' second Test win against Australia

"So it was all a big build up to it and interestingly, Dougie Morgan, who's a scrum-half who played for Scotland and who died last week - I remember Ian McGeechan saying that Dougie Morgan got into Gareth Edwards in a similar way - he stepped on his foot, he sort of rattled him a little, so I almost went into the game with that in mind.

"And early on, of course, it happened. I had the opportunity, it was a scrum, it was Australia ball, Nick Farr-Jones, who's a lovely man, a gentleman, came up just about to put it in and I thought: 'Right, what am I going to do?'

"So the foot came out. The size sevens went on to Nick Farr-Jones' foot.

"I exerted a bit of pressure. He didn't like it. He came into me and then this massive brawl erupted, which ultimately ended up in us probably taking control of the game.

"So yes, it's a bit of Ian McGeechan's nous in terms of getting me to do it and the physicality of our pack on the day with the English pack with Wade Dooley and Dean Richards and Paul Ackford and all these guys who really got the upper hand from that moment on and allowed us to win that game and control the third Test as well, which we won narrowly."

Campese's gaffe, Evans' winner

David Campese (11) could only watch as Ieuan Evans pounced to score the winning try for the Lions in 1989

The moment that decided the third Test and series was also one of the most memorable in Lions history. One of the game's most celebrated players, Wallabies wing David Campese, fluffed a counter-attack from his own line, allowing a Welsh icon - Ieuan Evans - to claim the decisive try.

Jones said: "David Campese tried to run from behind his own line and threw a pass to Greg Martin, the full-back, and it was a loose pass and Ieuan pounced and scored what ended up being the winning try in the Test series."

But had it not been for a Scotsman treading on a Welshman's foot all those years earlier, none of that may ever have come to pass.