Sprinter Dwain Chambers will be allowed to compete at the world indoor trials and national championships in Sheffield this weekend, say UK Athletics (UKA).
Chambers was well inside the qualifying time of 6.90 seconds
UKA chiefs will reluctantly let the 29-year-old run after admitting they do not have "sufficiently strong legal grounds" to stop him competing.
Chambers' legal team threatened to take action if he was not allowed to run.
UKA wanted to prevent him running as he has not undergone a drugs test since November 2006.
"To maintain the public's full confidence in our athletes and in the sport in general we want to ensure beyond all doubt that all athletes wishing to compete under the Union flag are drug-free," said UKA chief executive Niels de Vos.
I am relieved and delighted about UKA's decision allowing me to run on the weekend
"Our view is that all established athletes must participate in the out-of-competition testing programme for a continuous 12 months prior to competing for GB, Dwain is not in that position.
"However, we recognise that we do not have sufficiently strong legal grounds to refuse him an invitation given our published invitation policy.
"Reluctantly therefore, Dwain Chambers has been informed he is permitted to participate."
Chambers won the 60m at Sunday's Birmingham Games in 6.60 seconds to easily meet the qualifying standard.
The Londoner said: "I am relieved and delighted about UKA's decision allowing me to run on the weekend.
"I would like to thank Mr de Vos personally. As for the future, I just want to concentrate on Sunday and doing what I do best.
"It is now up to me to win the UK qualifier. We will take it from there."
Chambers will almost certainly have to win on Sunday to guarantee a place in the World Indoor Championships in Valencia from 7-9 March.
UKA's selection policy means they must pick the race winner but if Chambers finished second he is unlikely to receive the discretionary pick.
"Subsequent decisions on selection for the world indoors will be made in accordance with UKA's selection policy," said De Vos.
"It is, of course, not possible to prejudge, on a hypothetical basis, the outcome of that process.
"UKA have recently announced a full review of policy on doping offenders to ensure that in future all athletes, coaches and supporters will be clear as to the full consequences for those found guilty of using performance-enhancing drugs."
UKA had been reluctant to let Chambers run because they want to take a hard line on athletes returning following drugs offences.
I don't think UK Athletics have played this very well
BBC athletics commentator Steve Cram believes the organisation was too hasty in stating that Chambers had no chance of competing at the trials in Sheffield.
"I don't think UK Athletics have played this very well," he told BBC Radio 5 Live.
"I can understand Niels de Vos and Ed Warner (chairman of UKA) wanting to make a stance against drug cheats, but in this case they should have waited until they were in a strong position."
Cram added: "I don't think anybody wants Chambers running for Great Britain anymore and I really don't think he will."
Chambers tested positive for the steroid THG in 2003 and served a two-year ban, but returned to the sport in 2006.
The Londoner then chose to pursue a career in American football at which point UKA, believing he had retired, took him off UK Sport's drug-testing list.
UKA chief executive Niels de Vos insisted Chambers would have to undergo another 12-month period of out-of-competition drugs test before he would be considered for a Great Britain recall.
He has obviously cheated in the past but he's served his time and that's what the rules say
However, the sport's governing body, the IAAF, did not support that view as Chambers had not submitted a letter of resignation to themselves or UKA.
Chambers is currently ranked British number three over 60m behind Simeon Williamson (6.60) and Craig Pickering (6.57).
Both said they had no problem with Chambers returning to try and stake his claim for a place in the British squad for next month's World Indoor Championships.
"It doesn't really bother me that much," Pickering told BBC Sport.
"He has obviously cheated in the past but he's served his time and that's what the rules say, so I can't really have much of an opinion over and above that.
"I wouldn't particularly welcome him back as an athlete but I don't have a problem with him as a person."
Williamson added: "I train with Dwain, so if he goes through instead of me I'll be happy. I think he should be allowed to compete."
Chambers remains confident that he will receive the support of the majority of his fellow athletes.
"I think I've been humble enough and hopefully they can be a little bit more forgiving than most," Chambers told 5 Live at the weekend.
"I'm hoping that I can go out and gain everyone's trust again to show that I can run clean.
"I'm aware I'm not going to be everyone's cup of tea but for those that have supported me I'm very grateful."
Under UKA's selection policy, the winner of the 60m at the trials will automatically be handed a place in the British squad.