Chambers had an unsuccessful time playing American football
After serving a two-year drugs ban for doping offences in 2004, sprinter Dwain Chambers has struggled to re-establish himself on the athletics scene.
The 29-year-old returned to win gold at the 2006 European Championships, as part of the 4x100m relay team, but has since tried to launch a career in American football.
Now, after his brief gridiron career ended, athletics' world governing body, the IAAF, have cleared Chambers to fight for his place in Britain's World Indoor Championships team once again.
However, UK Athletics insists he will not be allowed to run as he has not undergone a drugs test since November 2006.
So, what exactly does the future hold for Chambers?
WHY IS CHAMBERS KEEN TO RUN AGAIN?
Before his fall from grace in 2004, Dwain Chambers was one of the world's leading sprinters and a genuine medal prospect for Britain at Olympics and World Championships.
After serving his two-year ban for taking steroids, he has been struggling to re-establish himself, flirting with a career in American football.
Last year, he signed a contract with the Hamburg Sea Devils in the NFL Europa league.
The competition has now folded and he needs to make a living after being forced to repay a huge amount of his earnings from track and field because of his involvement in drugs.
WHY ARE UK ATHLETICS UPSET ABOUT HIS POSSIBLE RETURN?
Neils de Vos, who took over from Dave Moorcroft as chief executive of UK Athletics (UKA) last year, is following a tough line on doping.
They realise that public confidence in the sport has been rocked by recent scandals like Marion Jones's admission of guilt and they believe they have to send out the right messages about fair competition.
To make the World Championships, he'd have to finish in the top two at the GB trials, in under 6.65 seconds
Chambers, they argue, hasn't been competing in athletics for the last 12 months and has not undergone any drug tests.
They don't think it is fair that, with his history, he should be allowed to line up at the GB trials for the World Indoor Championships alongside other athletes who have been available for drug testing over the past year.
On top of that, de Vos does not believe athletes who test positive should be allowed to compete for Britain again.
He'd like to change the rules so that can be enforced.
CAN UK ATHLETICS STOP HIM FROM RUNNING?
The stance of UKA is complicated, as under the previous executive, Chambers was allowed to run in a GB vest after serving his ban.
Chambers has not raced since the 2006 European Championships
He won a gold medal at the European Championships in 2006, in the 4x100m relay, before deciding to try his hand at American football.
He says he never formally retired from track and field. The IAAF say he didn't fill out the retirement forms and, as far as they're concerned, he has satisfied all their requirements for an athlete to compete.
Chambers's solicitor feels he has a strong legal case and that UKA have dealt unfairly with him.
On the face of it, UKA have a difficult job on their hands.
IS HE STILL A FORCE?
No-one knows for sure, apart from the small handful of people who've seen him train very recently.
The qualifying time for the GB trials is 6.90secs for 60m - and that should be within his capabilities.
To make the World Championships, he'd have to finish in the top two at the GB trials and run under 6.65secs.
The standard of entries for the indoor season won't be as strong as usual as many athletes will be concentrating on preparing for the Olympics and not doing the shorter races.
You'd have to say he'd be in with a chance.
HOW HAVE HIS FELLOW ATHLETES REACTED TO HIS POSSIBLE RETURN?
UKA say a lot of athletes believe there should be life bans for drugs cheats.
That's certainly an argument I've heard put forward by a number of people, but it's not a universal view.
When the World Anti Doping Association code was first drawn up, the consensus among lawyers was that anything more than a two-year ban for a first offence wouldn't be legally enforceable under restraint of trade laws.
Opinion is now shifting towards four-year bans again, while there are mechanisms in place like the British Olympic Association's bye-law which precludes guilty athletes from representing Great Britain at the Olympics.
In the end, clean athletes want justice but the punishments have to be proportional.