Across the world of sport, the issue of performance-enhancing drugs (PEDs) is under serious scrutiny right now. 

In boxing, it emerged that Dillian Whyte had tested positive for a banned substance ahead of his victory over Oscar Rivas, leading to accusations that he should not have been cleared to fight. 

Over in athletics, meanwhile, the Kenyan government are taking action to protect their reputation after a number of athletes were involved in doping scandals. 

Football might consider itself relatively immune from these problems, but it appears that couldn't be further from the truth. 

There are, of course, extensive measures in place to stop drugs cheats.

For example, Premier League stadia have anti-doping rooms where any player can be randomly tested after a game. 

However, The Mirror have released alarming details which suggest some players have escaped punishment in recent seasons. 

The newspaper report that a total of 11 Premier League footballers have been allowed to play despite having tested positive for PEDs. 

Over the course of 16 tests over three years, the players in question - who have not been named - were shown to have taken amphetamine, morphine, Ritalin or Triamcinolone, all of which are banned by UKAD (the UK Anti-Doping authority). 

The name Triamcinolone might be familiar, as it was controversially used by Bradley Wiggins before he won the Tour de France in 2012. 

In some cases, the FA chose not to take action against players because they accepted that the drugs were taken for medicinal purposes.

That would avoid the confusion surrounding cases such as Edgar Davids' back in the early 2000s, when the former midfielder, who has glaucoma, was found to be using medication which contained banned substances to treat the condition. 

More recently, others including Carlos Tevez have been given Therapeutic Use Exemptions (TUEs). 

So how big a problem is doping in football? The fact it's rarely talked about does seem strange for such a lucrative sport, as pointed out by the former World Anti-Doping Agency president Dick Pound. 

He's quoted by the Mirror: 

“For the largest sport in the world which is highly aerobic, the fact there are so few positive outcomes is a matter of suspicion in its own right.

“The real problem is most of the sports authorities do not wish to have positive tests. They think it’s bad for their reputation. They don’t want to invest in any major effort. My view when running WADA was that FIFA had little if any interest in digging into the problem."