The debate has been rather quiet for nearly two years now but it suddenly burst back open last month as Oscar Pistorius ran the 400 metres in a time of 45.07sec in a race in Lignano in Italy.

The significance of the time was that it meant the double leg amputee from South Africa, competing with the carbon fibre legs he runs on, had surpassed the A standard time of 45.25 which he needed to qualify for the South African team that will compete at the World Athletics Championships in Daegu later this month.

Since that day, South Africa has named the 24-year-old as its only 400m runner for the event and we find ourselves with the same question: "Should the 'Blade Runner' be allowed to compete against able-bodied athletes?"

The question itself dates back to 2007 when Pistorius took part in his first international competition for able-bodied athletes and began to draw complaints that artificial limbs gave him an unfair advantage over his rivals.

The same year, the International Association of Athletics Federations (IAAF) amended its competition rules to ban the use of "any technical device that incorporates springs, wheels or any other element that provides a user with an advantage over another athlete not using such a device."

The organisation rather bizarrely claimed that the amendment was not specifically aimed at Pistorius but they officially ruled on January 14, 2008 that the South African was ineligible for competitions conducted under its rules, including that year's Olympics in Beijing, following a series of scientific tests.

A battle followed as Pistorius employed the services of law firm Dewey & LeBoeuf to challenge the ruling and travelled to America to take part in a further series of scientific tests carried out at Rice University in Houston.

An appeal against the decision to the Court of Arbitration for Sport (CAS) took place in Lausanne in Switzerland and after a two-day hearing which concluded on May 18, 2008, CAS upheld Pistorius' appeal and the IAAF Council decision was revoked with immediate effect.

It was concluded that "not enough is known scientifically to be able to prove that Mr Pistorius obtains an unfair advantage from the use of prosthetics."

The IAAF President Lamine Diack was one of the first to welcome the move stating he is happy to see Pistorius compete.

"Oscar will be welcomed wherever he competes this summer," said Diack.

"He is an inspirational man and we look forward to admiring his achievements in the future."

The debate soon died down as for two years, Pistorius was no real threat to the top able-bodied stars.

Oscar Pistorius crossing the line ahead of rivals
He missed out on qualification for the Beijing 2008 Olympics and although he won three Paralympic gold medals in China, his winning time of 47.49 at the Paralympics was a symbolic mile behind the 43.75 American LaShawn Merritt ran to win the Olympic race.

Pistorius got gradually better in 2009 and again in 2010 but by this time the A standard time for the World Championships and Olympics had been set at 45.25, a time seemingly out of reach for the South African.

But on that night in Italy, the cat was right back among the pigeons as the South African ran a time not only good enough to qualify him for the World Championships and probably the London 2012 Olympics, but a time good enough to earn him fifth place in the Beijing 2008 Olympics.

At 24 years old, that time is only going to get faster meaning that Pistorius is now not only a potential Olympian, but a potential threat at the Olympics. This, more than anything else, has created problems.

Former British 400m star and Olympic silver medallist Roger Black has been particularly vocal on the issue.

"He was running okay times for the past few years but he was never going to challenge the best in the world and as long as he was doing that, it was fine," said Black.

"But now he is moving into territory which is starting to get interesting.

"If he gets down to 44.5 seconds, then it changes the whole discussion because nobody knows whether his blades are an advantage or not.

"They have not been around long enough.

"We don't know if Oscar is an amazing athlete, or a very good athlete with an advantage.

"What if a kid comes along with the talent of [world record holder] Michael Johnson but has an accident and then runs 41 seconds?"

"This is a whole grey area.

"I can only imagine how I would feel if I raced against him in the Olympics and he beat me.

"Now he is a real threat and a real player on the world stage, other athletes will say that it is unfair."

The argument here is that Pistorius is now a problem because he has shown he is now good enough to run times to challenge the elite.

Such an argument must be flawed and instead of asking what is making Pistorius so fast, perhaps it is best to ask how impressive it is that this athlete can continue to produce such impressive times with no legs?

Imagine the effort it takes to learn to walk with prosthetics, much less run and sprint at a world-class level.

This man is the very definition of disabled as he has no legs, yet is being questioned rather than praised for overcoming seeming insurmountable odds.

It is difficult not to feel sorry for someone who faces criticism for simply being the best he can be and someone who has to defend himself every time he runs his fastest race.

Having known Pistorius for a number of years, I am always astounded by the manner he conducts himself and the way he patiently argues his case when he is inevitably asked that same question again and again.

He will point to the scientific evidence that was strong enough to have CAS overturn the IAAF decision and he will politely state that the basis of his triumph is athletic ability rather than two plastic legs.

Perhaps the best comment I have heard on the subject comes from the International Paralympic Committee (IPC) President Sir Philip Craven.

"There are very few athletes who have the capabilities to compete in both the Olympic and the Paralympics," Sir Philip told me when we spoke not too long ago.

"It is an extremely difficult task even for those top Paralympic athletes but it is all about personal choice and it is up to the individual athlete to decide what they want to do.

"I have no problem at all with athletes such as Oscar wanting to compete at the Olympics and if it can help break down the barriers between the able-bodied and the disabled, then that is fantastic."

Jason_Smyth_Ireland_paralympian_11-08-11Pistorius is not actually alone in his quest as double Paralympic sprint champion Jason Smyth (pictured) has been named in the 17-strong Ireland team that will compete at the World Championships in Daegu.

The 24-year-old visually-impaired sprinter from Derry in Northern Ireland will compete in his specialist event the 100m and just like the Blade Runner, he will have his critics.

Perhaps this is rather harsh when a blind man and a man with no legs prove they are legitimately as fast as the world's elite able-bodied athletes, but so be it.

Smyth's case is a little more straightforward than that of Pistorius but the fact is when it comes to the South African, we may never really know if he does actually have an unfair advantage.

The only way to find out would be cutting the kegs off all the sprinters out there and seeing if they get faster on blades.

That is a trade I'm sure none of them would want to make but I'm sure Pistorius would love the reverse scenario for himself.

For my money, I feel the only advantage Pistorius' disability has afforded him is the relentless drive and desire needed to approach the accomplishments of his able-bodied peers.

But the simple fact is that Pistorius IS allowed to compete in able-bodied event and he will continue to do so until further notice.

And if it is good enough for the authorities, then Oscar Pistorius should be allowed to compete in able-bodied competition.

Should Oscar Pistorius be allowed to compete in able-bodied competition? Vote here.

Tom Degun is a reporter for insideworldparasport. To follw him on Twitter click here