Lucy Wright, who is due to give birth to her first child next month, will be allowed to stay in the country due to a "real risk" her human rights would be violated in an Argentine jail.
The 29-year-old faced up to 16 years in prison for trying to smuggle more than 6kg of the drug on a flight from Buenos Aires in 2007.
But after an initial court hearing she was bailed by Argentinean authorities before managing to escape across the border to Brazil and back to Britain.
Today, in an interview with the Guardian, Ms Wright told of her decision to become a drugs mule and her desperate efforts to escape imprisonment in Argentina.
She revealed that the Crown Prosecution Service is yet to decide whether to press charges on her case here and highlighted her beliefs that more needed to be done to address the implications of drug abuse.
"I want people to be aware of the knock-on effect, in terms of what has to happen for that cocaine to get into the country," she said.
"On paper, I am not the sort of person who should end up doing something like that. I come from a relatively middle-class background, I've got A-levels, I've been to university. One silly mistake can lead to something you would never have expected."
On March 20 this year, a high court judge ruled Ms Wright should not be sent back to Argentina to face her crimes.
Mr Justice Silber said that risked "widespread and systematic" abuses contrary to Article 3 of the European convention on human rights, which prohibits torture, and "inhuman or degrading treatment or punishment".
He said: "It seems clear in this case that the abuses which the appellant would suffer in Argentina are so widespread and systematic that there is a real risk of article 3 mistreatment."
Ms Wright's "silly mistake" was triggered, she claims, by the break-up of her first true love at university.
She was 24 and in her second year as a student nurse at Great Ormond Street hospital in London when her boyfriend left. "It was downhill from there," she said. "I went into self-destruct mode."
One day, she says, she asked a woman who was "clearly on something" whether she could give her anything to stay awake long enough to finish some overdue university essays.
Ms Wright says she was soon £30,000 in debt and later leapt at the chance to earn £20,000 during "a holiday" to South America. She added: "I thought she'd get me some speed, but she gave me crack. Within a week I was addicted. I had this mantra: I'd move out, pay back my debts and get back to nursing."
Ms Wright was arrested at Buenos Aires airport on 14 March 2007 after customs officers sawed open her suitcases and found packs of cocaine inside the metal frames. She picked up the drugs from a couple in Cusco in Peru. After being stripsearched, she was taken to a holding jail.
The following day she was bailed by a new judge who believed foreign drug smugglers should pay their own way while awaiting trial. She hatched a plan to flee Argentina and after catching local buses from town to town she eventually arrived in the frontier town of Puerto Iguazu. With no hope of catching a bus over the river Iguazu into Brazil without being arrested, Ms Wright says her "fight instinct kicked in" and she decided to wade across the river.
"I waited until it got dark and waded in in my jeans and flip-flops. The river didn't look too fast-flowing, but it was silty and muddy. I came out covered in mud, but no one saw me. When I made it, I remember just standing there thinking: 'What do I do now?' "I knew the British embassy was in São Paolo, so I had to make my way there - that took me four or five days." From there, she managed to obtain an emergency passport and fly home to Britain.
Ms Wright added: "I think it's very narrow-minded of people to separate society so definitely. That homeless person on the street, that beggar, that sex worker, a drugs mule - they're not in another world from you.
"Three years ago they might have been in very different situations. The line between them and you is thinner than you think."