The Commonwealth Games has witnessed arguably its most gripping and distressing moment when Scotland’s Callum Hawkins collapsed while leading the men’s marathon just two kilometres from the finish line.

Hawkins had looked set for a comfortable victory when he opened a lead of more than two minutes over Australia’s Michael Shelley.

But in the closing kilometres Hawkins began to be affected by the heat, with the temperature having reached 28 degrees by the late stages of the race.

He started swaying towards the roadside curve and even crashed into the spectator area next to the course just ahead of the Sundale Bridge in Southport.

Australia’s Michael Shelley passes the sprawled Callum Hawkins on his way to claim marathon gold.  Photo: AAP/Tracey Nearmy

The 25-year-old got back on his feet but was clearly in discomfort as he struggled to make his way across the bridge and more than once he needed to use the roadside barrier to prop himself up.

Hawkins had only just passed the 40km mark when he crashed into the bridge railing and collapsed on the road, unable to get up.

It was little surprise Hawkins could not finish the race, such was his physical distress, and after race officials attended to him on the course he was taken to hospital for a medical review.

Shelley admitted he too was struggling, especially with the wind playing havoc along with the hot conditions.

“I saw him (Hawkins) at about the 40km mark and I thought ‘jeez, I might still be a chance here’,” Shelley said.

“Then a couple of hundred metres later the legs started giving me the little wobbles and I was like ‘Oh jeez, I could be on the road myself in about 500 metres’.

“So getting up that last little hill was brutal and I saw the wind start to get me as well.”

At this stage the official lead over Shelley was two minutes and three seconds. Hawkins was forced to watch the Australian, who did not look at his opponent as he lay on the ground, run by on his way to a second consecutive Commonwealth Games gold medal.

Friends along the course had alerted Shelley to the fact Hawkins was in distress, while he was dealing with his own physical demons.

“I was starting to go myself,” Shelley said. “I was starting to get little cramps in my hand, stuff like that. So it was quite difficult at the time.”

In his mind Shelley had settled for the silver medal, as the “jelly legs” took effect.

He had noted Hawkins had picked up the pace considerably between the 25km and 30km checkpoints.

“I was like ‘Oh jeez, here we go. This could be a long day at the office’,” Shelley said.

Scotland’s Robbie Simpson finished third, despite the fact he “could feel the legs going”.

He was disappointed for his teammate after seeing the state he was in when he went past at the 40km mark.

“He was going so well,” Simpson said.

-ABC