World record holder Diniz – a good friend on the circuit of Heffernan - pushed the tempo right from the very start.

An early attempt to break clear saw him reeled in by Mexican Horatio Nava, with Diniz moving back into the main bunch containing the Irishman.

This, though, was just to conserve energy, as at 8km Diniz went strong again, once more bringing Nava with him – but not for long.

With the Mexican athlete finally burned off, Diniz would pound the rest of the field the way he was pounding the streets of London.

The three-times European champion – but with only a world silver from Osaka ten years ago on the global stage - kept building his lead to a point where by halfway, he was over a kilometre clear.

The strong pace affected some.

With the field looking to keep some sort of contact with the runaway leader, Heffernan fell off the back at the 8km mark to lie 13th in a second chasing group.

While this wasn’t drastic at first - the gap between Heffernan and the chasers remaining constant at 10-12 seconds across the next dozen kilometres – an increase in speed from those ahead of him saw the Leevale AC pacer fall even further back in time and placing.

By the 30km mark, Heffernan had fallen to 20th and fears were growing that he might go even further back.

But that was as low as the Corkman would fall, as the 2013 world champion kept his trademark calm resolve, putting in his usual confident and strong final half of the race to pick off tiring athletes and the disqualified.

Onwards he rose – 18th at 34km, 15th at 38, then 11th by the 41km point… and it would continue in this vein.

Heffernan hit the top ten for the first time with five kilometres to go, by overtaking João Vieira of Portugal and New Zealand’s Quentin Rew.

German Carl Dohmann was the next to be nobbled, and even though Heffernan had a big joust across a late burst of a thousand metres with Italian Marco De Luca, eighth position was secured in the final two kilometres.

Heffernan’s time of three hours, 44 minutes and 41 seconds may have been three minutes off the medals, but his eighth place maintained some pride on a day of large Irish support in the London sun.

Diniz clocked a Championship record of 3:33:12, finishing a massive eight minutes clear of Japanese silver and bronze-medallists Hirooki Arai (3:41:17) and Kai Kobayashi (3:41:19). Igor Glavan of Ukraine was fourth in 3:41:42.

Announcing his retirement, Heffernan said after the race: “It was a tough race today but I had to turn it into a positive. The last 10km, I was back to my old self.

“I’ve had a great career and it was a good note to go out on. I’d like to thank my team and everyone who has supported me.”

Referring to the thousands of enthusiastic spectators watching on from the 7:45am start, many of whom were Irish, Heffernan added: “It was the Irish crowd, the familiar faces of everybody who supported me.

“The motivation for me today was to give them something positive, to give them something to say thanks.

“I could have been putting my head down and feeling sorry for myself when I wasn’t going to win a medal, but it was lovely to thank people.

“It was lovely to come here, and lovely for them, to give something back – and from the bottom of my heart, I’d really like to thank everybody who has supported me, and that’s what has been keeping me going this year.

“It’s been emotional.”

In terms of his retirement, which was confirmed after the race, Heffernan still quipped: “Never say never. I might have to re-evaluate my marriage situation though.”

Heffernan’s wife and coach, the former Irish international sprinter Marian Heffernan, is looking forward to seeing Rob at home a lot more from now on: “I’m very proud of him, so happy that he’s finished – there’s a double meaning to finished!”

The Corkman operates a high performance centre of walking in Cork, and will concentrate on this in future: “I know the life you have to live as a high-performance athlete, and that’s where my passion is now – giving back.

“Even someone like Brendan Boyce, who I took on as a project, or the other walkers I took on who took European Cup medals this year - that went a bit under the radar, it was the first time Ireland ever won (senior) medals.

“Why? There’s no big secret – it’s work. It’s work.

“The sport is so poisonous now with talk of just doping all the time.

“We’re forgetting the main ingredients of what makes our athletes good – what made Marcus good, what made Sonia good, what made the Dick Hoopers good, and all the good marathon runners back in the day that we trained.

“They all trained very hard.”

The 2013 world champion was also critical of the non-screening of the Championships on Irish television – one of only five out of fifty European nations not screening it on domestic TV, though coverage from the BBC and Eurosport is available to 90% of the country.

After a poor week overall for Ireland, Heffernan’s high finish finally puts the country onto the top-eight placings table – on the final day - which reflects strength-in-depth at Championships as opposed to just medals.

Ireland last failed to appear on this list in Helsinki in 2005, when Karen Shinkins provided the top Irish finish in 19th, in the 400m – the exact same finishing position and event of Ireland’s previous best performer in London, Brian Gregan.

Heffernan’s long-standing team-mate Brendan Boyce was forced out on the eve of the race due to a hamstring injury picked up in training on Tuesday.

Alex Wright was the final Irish competitor in action this week, competing in the men’s 20k walk.