Mark Lewis-Francis has revealed that he is just one missed drugs test away from serving a one-year suspension.
Lewis-Francis blamed a broken doorbell for one of the missed tests
Lewis-Francis missed tests in 2005 and 2006 and the 25-year-old is well aware that one more mistake in the next three years would trigger an automatic ban.
"I have two strikes. I am on the final line, I am on the wire," he said.
"My two are for being lazy. It was while the system was brand new and they should have given us a bit of leniency. I think it's a rubbish system."
The 25-year-old sprinter, who took an Olympic gold as part of Britain's victorious 4x100m relay team in 2004, explained the circumstances of his missed tests, which are held on British athletes' records for five years.
I feel like I am back at school and have to report to the headmaster everywhere I go
"They both happened when I first moved from Birmingham to train in the south," he said.
"On the first occasion, I was living in a rented house where the doorbell didn't work.
"Then the testers called when I had left to stay in London, before last year's Crystal Palace meeting.
"I do not understand why they are singling us out as British athletes. We are not the biggest cheats in the world.
"Now I would never miss a drug test. I have told UK Sport that I will be at home between 7am and 8am, and if that changes I have to report every move.
"You have to live with it. I feel like I am back at school and have to report to the headmaster everywhere I go. But if it keeps me on the track and means I can be an international athlete, it's worth it."
Christine Ohuruogu was the last British athlete to miss three drugs tests and was subsequently banned from all competition.
She returned to win gold in the 400m at the World Championships in Osaka in August and her appeal against the Olympic ban was successful last week.
At Ohuruogu's appeal, it emerged that three other British athletes were on the brink of suspension having missed two drug tests.
Becky Lyne, the European 800m bronze medallist, and Simeon Williamson, the European Under-23 100m champion, had already been named before Lewis-Francis's admission.
Lewis-Francis tested positive for cannabis in 2005 and was stripped of his silver medal won at the European Indoor Championships in Madrid in the same year.
He was publicly warned by UK Athletics, but avoided a ban because the organisation accepted the drug was in his system passively and had not been used to enhance performance.
The British Olympic Association agreed to overturn his automatic Olympics ban for the offence in August 2006.