BBC Sports Correspondent Adam Mynott reports: "Some of the doping procedures need to be re-examined"

The 39-year-old athlete has vehemently denied taking the substance to boost his performance, after traces of nandrolone were discovered in a urine sample at an indoor meeting in Germany in February.

Sports Minister Kate Hoey said in a letter to UK Sport's chairman Sir Rodney Walker, that its system was the "most thorough and rigorous in the world".

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But she went on: "A review of procedures will help to identify those areas which can be developed and those which work well.

"It is essential that the UK's drug testing system retains the respect of those competitors it is meant to protect, the confidence of the governing bodies who may have to undertake complex, lengthy and expensive legal proceedings, and members of the public, who need to be sure that the races they see produce genuine results."

'Test flawed'

Christie meanwhile has vowed to removed the slur on his name.

"I am completely innocent of any wrongdoing and any case against me will be vigorously defended.

Linford Christie: "I'm going to clear my name one way or the other"

"I have consistently opposed the use of banned substances by athletes and it is ridiculous to imagine that I would take them after my retirement," he added.

Fellow athletes have also rallied to his defence and called for a more reliable testing procedure for nandrolone, which occurs naturally in the body.

World triple jump record holder, Jonathan Edwards, condemned Christie's positive test result as "utter nonsense".

Sally Gunnell is backing Christie's fight to clear his name

He said: "There's one Spanish doctor who will not accept as positive any test related to metabolites of nandrolone, because he thinks it is so flawed."

Nandrolone was the substance at the centre of 200 metres runner Dougie Walker's recent suspension and subsequent acquittal.

Lawyer Nick Bitel who represented him in the case said: "Athletes, footballers, people from all different types of sports around the world are suddenly failing for nandrolone.

"There's been an explosion of cases and even UK Athletics' own doctor accepted today that we don't know enough.

Professor John Henry of St Mary's Hospital in London explains why Linford Christie may have tested positive

"We don't know why this is happening and yet the poor old athlete is faced with being banned and losing his good name and livelihood."

Sally Gunnell, who captured gold after running the 400m hurdles in Barcelona, wants a complete overhaul of the drugs testing scheme.

She said: "The bottom line is, how are athletes feeling when they are out there now?

"I think they must be thinking every time they go for a test is this nandrolone going to be showing up again? I think UK Sport has to look into it."

Brendan Foster: "At the end of the day, Linford Christie is not a cheat"

Sports commentator Brendan Foster said scientists had to have a watertight case before they announce that athletes have failed drugs tests.

The middle distance great told BBC Radio 5 Live: "Until it is 100% how dare they bring the name of an athlete like Linford Christie into question?"

Urgent inquiry

UK Athletics, the sport's governing body, has said it will arrange a disciplinary hearing as quickly as possible to examine the drug allegations against Christie.

Dr Malcolm Brown, director of medical services at UK Athletics, told the BBC: "What's lacking is sufficient scientific research for these findings over the last year.

"There have been a number of reports of athletes around the world having metabolites of nandrolone and this is very odd.

"We need to look at both sides and not jump to conclusions."