IT might seem like a harsh line to adopt but, when it comes to drug offences in sport, ignorance can never be an acceptable excuse.

Middlesbrough defender Abel Xavier will release a press statement this morning in which he will protest his innocence following last night's confirmation of a failed drugs test.

The 32-year-old international has been battling against a virus for much of the last month and is expected to claim that American supplements he had been taking could have contributed to a positive test.

Perhaps they did, and perhaps Xavier has been guilty of nothing more than naivety.

Maybe he has listened to bad advice and assumed there was nothing untoward in the supplements he was taking.

Either way, it should not matter when UEFA officials meet to discuss his case on Monday.

This is not simply a matter of right and wrong - it is an issue that threatens to undermine the very integrity of sporting competition.

If random drug-testing is to mean anything at all, a positive test must be a positive test whether the sportsman has been complicit in it or not.

Pleading ignorance is simply not good enough. Once one person is allowed to pass the buck, everyone will inevitably follow.

Adopting a strict liability rule is the only way of ensuring that sporting competition takes place on a level playing field.

It might not seem fair at the time, but the alternative is an anarchical system where drug cheats are able to avoid punishment by hiding behind a range of obscure products linked to substances that are banned.

After all, it is not as if sports stars can claim to be unaware of the consequences of their actions.

In 2002, in a case that appears to have parallels to Xavier's, British skier Alain Baxter was stripped of a bronze medal after testing positive for the banned substance methamphetamine.

An emotional Baxter claimed the positive test had come from his use of an over-the-counter nasal inhaler he had bought in the United States.

The IOC sympathised with his plight, but still took away his medal and banned him from competitive skiing for six months.

Harsh, but ultimately fair. When the multi-million pound industries of sport and pharmaceuticals collide, it does not take much to imagine a situation where banned drugs are purposefully included in seemingly innocuous supplements in order to provide a convenient cover for wrongdoers.

Professional sportsmen and women have a duty to monitor everything they use or consume. It should not be too hard from them to avoid falling into the traps that undoubtedly exist.

If Xavier is to claim that it was ignorance rather than ill-intent that led to a positive test, he does not have a leg to stand on.

Surely, when considering taking a new set of supplements, he should have checked the exact make-up of what he was about to put in his mouth.

Modern-day football clubs employ an army of nutritionists and dieticians - it is inconceivable to imagine that a quick answer would not have been provided had he posed the question.

Ironically, the 32-year-old has long made a major issue of his diet and nutritional well-being.

In the build-up to the 2002 World Cup, he gave an interview in which he revealed how carefully he monitored what supplements he took.

"There is nothing more important for an athlete than nourishment," he explained at the time. "Our bodies are like cars and we must know the exact effects of how we feed them.

"I want mine to be perfect and it won't be if I don't give it the best oil and gasoline. It's my most important tool and I take religious care of it."

Those words may well come back to haunt him but, should his B-test also prove positive when it is checked later this month, FIFA cannot afford to show him any leniency if he claims he is guilty of nothing more than an oversight.

To their immense credit, the English FA stood firm when Rio Ferdinand failed to turn up for his drugs test in September 2003.

Ferdinand claimed he had simply forgotten the test was due, while Manchester United argued that, by passing a test two days later, their centre-half had proved his innocence.

Concluding that a missed test equalled a failed one, the FA dished out an eight-month ban that served as a warning to Ferdinand's contemporaries.

FIFA must do the same with Xavier.

It will be unfortunate for the player and unfortunate for Middlesbrough, but both parties need to look at the bigger picture.

Ensuring football remains drug-free is more important than pandering to more parochial concerns.

Read more about Middlesbrough here.