We cannot unknow what we know. Worse still we cannot help but draw conclusions from what knowledge we have.

Those of us who have lived through the scandals of the East German medal machine in the seventies and eighties; ‘the world’s dirtiest race’ in the eighties; the ejection of Russians from the last Olympics because of ‘state-sponsored doping’; and who have been appalled when many of our own local heroes have been exposed as dopers, find it hard not to be cynical in this post-Rumsfeldian world.

We cannot unknow that there remains an on-going investigation into the methods of Alberto Salazar, the man under whom Mo Farah has achieved most of his success, inviting speculation that the coach’s expected absence from London this week is because of the level of distraction both know it would generate. We cannot unknow that Farah offered a defence that many found implausible when claiming that the reason he had missed a dope test was that he had not heard his door bell being rung.

We cannot unknow that officials of the World Anti-Doping Agency reported that Jamaica, homeland of Usain Bolt, the greatest sprinter of all-time, failed to operate anti-doping procedures in the build-up to the London Olympics at which his status was confirmed when he repeated his Beijing Olympic 100m and 200m double. We cannot unknow, either that there is evidence which indicates that athletes who have taken performance enhancing drugs can benefit from the effects for many years afterwards.

We cannot unknow that sport’s most notorious drug cheat, Lance Armstrong, charmed and intimidated all around him to remain silent about what they knew and would never have been caught out had he not riled one of the few sports journalists who was backed by resources unavailable to most in the profession these days and was blessed with the tenacity to pursue the story for 13 years. Farah must surely have known, or had it explained to him, that when claiming he would never submit a positive test he was echoing the sort of legalistic sounding phraseology adopted by the Texan.

Perhaps most worryingly of all, we cannot unknow that the International Association of Athletics Federations (IAAF), currently still run by people who were involved at the highest level when that organisation was exposed as being corrupt at its core, is well aware of what is at stake should another of its big brands prove to be damaged goods.

What we consequently think we know represents sufficient circumstantial evidence for many to be convinced that there remains cause for concern. Others, many of whom would prefer not to know what the rest of us know, are meanwhile incensed by the very notion that any doubt should be cast over the purity of the two great heroes of this generation of track athletes.

So, to what we know for certain.

We know Mo Farah – four time Olympic, five time World and five time European gold medallist - is a man blessed with a formidable combination of East African genes and western world resources at a time when the acquisition of medals has become the most important sporting priority of the British political classes.

We know, too, that Usain Bolt – eight time Olympic and 11 time World Championship gold medallist - is the first man of such height to find a way of getting his legs moving quickly enough to prevent his rivals from becoming uncatchable in the first 60 metres of 100m races. Those of us who delighted in the ‘Superstars’ programme in what felt like a much more innocent age and, in particular, marvelled at the way Andy Ripley, the powerhouse English back-row forward, could reel in the best athletes from other sports and wondered what might happen if he could find a way of getting off the start line more quickly, reckon we may have our answer when we see Bolt in full flight.

Just as there is powerful circumstantial evidence to raise questions so there is a compelling case to be made that these men, who have both repeatedly proclaimed their commitment to ‘clean’ competition, Bolt most recently in the build-up to these World Championships when stating his sport is at ‘rock bottom’ and that it must be cleaned up or will die, are true champions in every sense.

History has told us that it is as foolish to cling dogmatically to either argument and the vast majority of sports lovers can merely hope that any suspicion is merely built upon ill-founded, if understandable hypothesis at best and conspiracy theory at worst. That it remains and is wholly plausible after such a lengthy opportunity to subject these men to the fullest possible scrutiny, is deeply sad, but we rely upon the notion of innocence until proven guilty for all that we cannot unknow how little incentive there is in a brand-driven sporting world for the various authorities to assist in the process of investigating their superstars.