But when asked whether Kigen had slowed at any point to let him catch up, Farah responded with a laugh: "No".

Asked if he could have broken away when he opened up a five-metre lead at 10 miles, Kigen responded: "No I couldn't. I'm happy with second place. I was trying to push but I know Farah in the last mile is so strong."

Three days before the Great North Run, the manner of Australia's 91-83 defeat by Angola in a FIBA Basketball World Cup group match triggered more serious suspicion, to the point where the International Basketball Federation announced they were opening disciplinary proceedings against the losers.

After resting several of their strongest players, including star centre Aron Baynes, the Australians - who subsequently lost their quarter-final against Turkey by a single point - let a 15-point lead slip against their African opponents.

Australia's defeat by Angola at the Basketball World Cup last week is now being investigated by the world governing body ©AFP/Getty Images

A FIBA statement read: "The on-court behaviour displayed by Australia in that game generated huge disappointment by basketball fans and experts.

"It is widely suspected that Australia lost that game in order to avoid having to face the reigning world champions USA until the semi-finals."

Basketball Australia plans to make a vigorous defence of its team, saying in a statement:

"The Australian Boomers went into the game against Angola to win - plain and simple.

"Claims to the contrary are widely speculative, insulting to the Australian sporting culture and to our playing group who gave their very best throughout this tournament.

"They're downright wrong."

Farah has denied any fixing; and as matters stand, no charges are proven against Australia's basketball team.

But these two cases are merely the latest examples to have occurred in two sporting areas which have, historically, generated suspicions and ambiguities down the years.

Farah's phrase "how high he thinks of me" is interesting. The obvious interpretation, backed up by Kigen's comment, is that the Kenyan runner simply did not believe, given what he knew of Farah's talent, that he could realistically hope to break away and win. But there is an element in this phrase also which hints at something beyond respect. It almost suggests Kigen would think it wrong to challenge Farah.

Only Kigen will know the truth of the matter.

It is well acknowledged that middle distance and longer distance running has always involved elements of collusion in races - unofficial partnerships or agreements between competitors, often but not always of the same nationality, even in races were overt assistance is being offered in the form of pacemakers travelling at speeds agreed by the main players.

At the 1993 International Association of Athletics Federations World Cross Country Championships held in Amorebieta. Spain, running as a team was an intrinsic part of the event, given that the team championship ran in tandem with the individual race.

But such was the Kenyan domination of the race that they were able to openly manipulate the individual honours at the same time as securing their national victory. After William Sigei - who would break the world 10,000m record the following year - had taken the gold, it transpired he had been effectively waved through by his fellow Kenyans on the instruction of their coach, who explained to me and other questioning members of the press afterwards that Sigei had proved himself the best runner in training.

Sigei's victory in the men's senior event, which was led for all but the finishing straight by his teammates Dominic and Ismail Kirui, was worked out to the last detail. "In the last five hundred metres I slowed my speed so that Sigei could come through," Dominic Kirui said. "In our training before the race, when we were doing speed work, we saw that Sigei was just better. It was decided that Ismail and I would make good pacemakers for him."

The man who laid the plans, Kenya's national coach, Mike Kosgei, beamed with pride afterwards. "Sigei was our darling in the race," he said. "When he was running on his own in third place, I told him to stay there. We didn't want anybody to jostle or spike him."

Moving back to the case of the Australian basketball team - however the allegations play out, this is no more than the latest instance of suspicions being raised because of a competitive framework which is open to the possibility of manipulation.

At the 1982 World Cup finals, similar disquiet was raised by the final Group B match between West Germany and Austria. Because all the other qualification matches had already been played, the two neighbours were able to go into their meeting knowing exactly what they needed to do to ensure progression.

A 1–0 win for the Germans would suit both teams perfectly. Horst Hrubesch put West Germany ahead after ten minutes, after which the match effectively ended as a competition. Despite boos and whistles from the crowd the phoney contest continued until the final whistle.

Algeria, the team that missed out on qualification in the same group, protested to FIFA, but to no avail. However, at the Mexico World Cup four years later, FIFA ensured that the last round of matches in the group stage took place simultaneously.

West Germany's Horst Hrubesch celebrates scoring the goal which earned his side a 1-0 win over Austria in a Group B match at the 1982 World Cup which saw both teams progress to the next round, provoking a protest - and a subsequent rule change ©Getty Images

At the 2009 Asia Pacific Bowls Championships in Kuala Lumpur the New Zealand four skipped by Gary Lawson - a player who had been gloriously described as "the Bad Boy of New Zealand bowls" - were accused of throwing their last group game in order to manipulate a better draw in the knockout stages. The consequent maths within their group meant that Canada missed out on progressing, and the Canadians, suspicious, asked Bowls New Zealand to investigate. All were reprimanded, and Lawson was banned for six months.

Three years after the Bad Boy had become the Banned Boy, there was a similar to-do over deliberate defeats - but this time the sport was not bowls, but badminton, and the controversy took place at the London 2012 Olympics, as bad luck would have it, on the day when the International Olympic Committee's President, Jacques Rogge - who had sounded a clear warning on the danger of match fixing in world sport a year before the Games had got underway - had been a spectator at the Wembley Arena on the day.

Four of the teams in the women's doubles were disqualified on the ruling relating to "not using one's best efforts to win". Matches between two South Korean pairings and their Chinese and Indonesian opposition turned into a shuttlecock version of a slow bicycle race as the teams appeared to be outdoing each other in their efforts not to win, methods of which included deliberately missing shots and serving woefully.

An official steps during a badminton match between Indonesia and South Korea at the London 2012 Olympics. Eight players in the women's doubles competition were disqualified for not using best efforts to win ©Getty Images

The expelled players included Chinese world champions Wang Xiaoli and Yu Yang, who were accused by other players of attempting to throw their "dead rubber" game in order to avoid playing China's number two ranked pair before the gold-medal match. The Chinese players' actions appeared to trigger a response from pairs from South Korea and Indonesia, who in turn tried to lose to counter the Chinese intentions.

Thomas Lund, chief executive of the BWF, made a careful statement to reporters in the aftermath of the controversy: "I would like to underline that it is the responsibility of the players, and team members, and the entourage around them to live up to the standards in our regulations - the players' code of conduct - to go after winning every match. That's the bottom line."

But the competition format was subsequently changed so that the same temptation will not be there at future Olympics. Sometimes that's all it takes to erase the grey areas in sport. Sometimes the answer is not so simple.

Mike Rowbottom, one of Britain's most talented sportswriters, covered the London 2012 Olympics and Paralympics as chief feature writer for insidethegames, having covered the previous five summer Games, and four winter Games, for The Independent. He has worked for the Daily Mail, The Times, The Observer, The Sunday Correspondent and The Guardian. His latest book Foul Play – the Dark Arts of Cheating in Sport (Bloomsbury £8.99) is available at the insidethegames.biz shop. To follow him on Twitter click here.