Graeme Souness sent a pass down the Dutch left. Kenny Dalglish picked it up. Dalglish shielded the ball but Jan Poortvliet got a toe in. The ball ran loose.

History intervened; Archie Gemmill landed. Around 25 yards out, a line of Dutch defenders in front, Gemmill skipped one challenge, slalomed right and slid the ball between Ruud Krol and Wim Jansen. Suddenly only Dutch goalkeeper Jan Jongbloed was before him. Gemmill curled the ball into the far corner.

June 11th, 1978, Mendoza, Argentina: Scotland were 3-1 up against the Netherlands in the World Cup.

Planet football knew it had just witnessed a goal for all time, and behind the net where Gemmill scored, a 24-year-old footsoldier in the Tartan Army, from Glenrothes in Fife, knew too. He scaled a crush barrier to celebrate in his kilt. Argentinian locals held him aloft.

Unknown to any, a photographer captured the moment. The resulting photograph, reproduced here, is of Colin “Pid” Weddell. This is the story of that picture.

Funnily enough, it begins in a bar.

Once Scotland had sealed qualification for Argentina, ahead of reigning European champions Czechoslovakia, Weddell and a friend, Graeme “Gaigse” Walker met in the Halfway House (recommended) near Edinburgh’s Waverley station.

Pid and Gaigse had a few. They came up with a plan: Destination Cordoba, June 3rd, 1978, Scotland’s World Cup opener against Peru.

They invited another friend living in Canada, Iain “Ginger” Brannen. And so, on Tuesday, May 23rd, Pid, Gaigse and Ginger set off; distance 9,500 miles. Not a word of Spanish between them.

Fortunately, Weddell kept a diary and in Edinburgh’s Guildford Arms (recommended), he passed on a copy. Ominously, its introduction contains the phrase: “Anyway, the master plan was simple.”

Weddell was working in Lancaster in 1978. He was an early computer programmer, a smart young man. He gave that up to go to South America.

First stop was Trinidad. "Well-placed" is the diary description of the Caribbean island. But when the Tartan trio arrived in Port of Spain, they realised Córdoba was still some 5,000 miles away.

There was a consolation, though. As Colin noted: “Some magic-looking women around.”

Next, a flight to Caracas, Venezuela. Once there the trio headed for the local bus station and after “12 hours on a bus packed with people, chickens and goats”, they arrived in the Venezuelan border town of San Antonio. Just 4,300 miles from Córdoba.

Colin writes: “Walked over the border into Colombia guy at a supermarket changed some money found helpful taxi driver who drove us back into Venezuela where we changed more money Colombia again to the airport at Cucuta booked flight to Pasto near the Colombia/Ecuador border cost, 2113 pesos each (70 pesos = £1, so £30) idea to save time but also we were worried by bandito stories . . . still can’t believe how beautiful the women are."

By June 26th they were in the Ecuador town of Tulcan. “None of the banks would change traveller’s cheques. The only place we could get these changed was in the capital, Quito – 250 miles away. The bus to Quito cost us 50 sucres (£1).”

It took seven hours. Quito, built at 9,000 feet, is 3,500 miles from Córdoba. “On the way we passed Mount Cotopaxi, the highest volcano in the world sent a postcard to the folks.” By June 29th they were in Lima, Peru – “a very interesting and dangerous city main activities, watching the tanks rolling up and down, playing chess at small tables on the pavement.”

Their hotel cost 65p a night. In Arequipa in southern Peru, fewer than 2,000 miles from Córdoba, they witnessed a shooting at the bus station. And when the next bus broke down “on the shore of Lake Titicaca we began to realise that we might not make Córdoba for Peru.”

Colin’s diary records: “Thursday, 1st June, 1978. Opening day of the World Cup.” But he, Gaigse and Ginger were in a Peruvian town called Puno. They were en route to La Paz, Bolivia. More tanks. “We were caught up in a military curfew.” Waking the day before Scotland-Peru, 1,425 miles from the game, they tried to book a flight, but couldn’t. So began a 30-hour train journey, which meant as Ally MacLeod readied his team, the boys from the Halfway House were in Bolivia.

“We were all very much down in the dumps.” On the train they heard that the score was 1-1.  On June 4th they walked across the Bolivia border into La Quiaca. At last they were on Argentinian soil. After (another) 10-hour bus journey they were in Salta. They discovered that 1-1 was the half-time score against Peru. Teofilo Cubillas had yet to deliver his two. Things were not getting better. But finally, on Tuesday, June 6th: Córdoba. They had been travelling a fortnight, seen Trinidad, Venezuela, Colombia, Ecuador, Peru and Bolivia and missed the first Scotland game by three days. But they were here. And Scotland played Iran in Córdoba on June 7th.

“This turned out to be the worst game we had ever watched, with Scotland only just managing a draw with the aid of an own goal. To think we had travelled 10,000 miles for this.” Four days later, they had headed west to Mendoza, scene of Archie Gemmill’s goal and Colin Weddell’s photograph. But after Gemmill’s goal, his second, Johnny Rep made it 3-2, and Scotland’s World Cup was over on goal difference. The Halfway House trio had to get home. A mere 13 days later, they were back in Trinidad. From there it was a long flight to London but, oh, the tales to be told.

On the morning before Colin landed, his father Andrew went to work as usual in the Frances coal mine in Dysart, Fife. Andrew Weddell loved his job. He was killed in an underground accident along with a 17-year-old apprentice. Colin’s mother Helen, now 83, said that Andrew had been “so excited” to hear his son’s stories. Colin was so excited to be telling him. Only one postcard had made it home by then. Archie Gemmill didn’t matter. It was a while later that a friend asked Colin if he had seen a Scottish football book. It was there that his photograph was published.

"I'd no idea," Colin says. "When I first saw it I was a bit embarrassed. It was all a bit of a blur." Pid, Gaigse and Ginger stayed supporting Scotland – they went to France 98 together – and Colin was in Glasgow last November, though he won't be in Dublin today. Six years ago, he went back to Mendoza. A local taxi driver helped him sneak inside the stadium. He showed the man a photocopy of the picture of him from 1978. The taxi driver disappeared. When he returned it was with an old, Argentinian newspaper, dated "12/06/78". It was from the day after Gemmill's goal. There, in print, in his kilt, was Colin Weddell. As we know now, that's only part of the story.