With relations between the UK and Argentina already strained over the Falkland Islands, top judges decided conditions in the country's prisons are "inhuman and degrading".

British tourist, Lucy Wright, 28, from south east London, faced extradition after she was caught trying to smuggle over 6kg of cocaine through Buenos Aires airport in 2007.

But the High Court accepted the lack of the most basic hygiene and food in the jail in which she would serve up to 16 years - along with evidence of "systematic abuse" of prisoners by jailers - meant sending her back to south American would breach her fundamental rights.

Mr Justice Silber said Wright had "freely admitted" being a drugs mule, but says the cocaine haul was targeted at the UK, nor Argentina, and has said she will plead guilty if prosecuted in this country for her crime.

The court heard evidence from Argentinian civil rights lawyer, Dr Maria del Carmen Verdu, that Wright, if extradited, would be at risk of dire hygiene standards, inadequate food, "systematic abuse" by prison staff and "cruel punishment and degrading searches".

Dr Verdu said food was so short in Argentinian jails that prisoners have to rely on relatives and friends to bring them supplies and, having none of those, Wright would face starvation.

"It seems clear that she would not receive even basic supplies of food and hygiene products if detained in an Argentinean prison", said Mr Justice Silber.

He added that records examined by Dr Verdu from 2009 revealed that more than half of inmates were "beaten or tortured during their fist contact with prison staff". Almost 80% of prisoners were also injured during brutal and invasive searches.

"The uncontradicted evidence shows a disturbing pattern of cruel, inhuman treatment being suffered by female prisoners and especially foreign ones in Argentina. So, it is very likely that Wright would be subjected to this treatment," the judge said.

"The picture that emerges on the uncontradicted evidence is of frequent bodily and cavity searches carried out on female prisoners often when they are completely naked and in the presence of males. Wright would have to suffer this if detained in an Argentinean prison".

Wright's lawyers argued extradition would breach her rights under Article 3 of the European Convention on Human Rights which bans inhuman or degrading treatment or punishment.

And the judge said: "It seems clear in this case that the abuses, which Wright would suffer in Argentina, are so widespread and systemic that there is a real risk of Article 3 mistreatment.

"In other words, she should not be extradited because to do so would affront well-established authorities that humanitarian principles prevent a country from removing an individual to a country where he or she is foreseeably at real risk of being seroiusly ill-treated."

Mr Justice Silber emphasised that his decision on Wright's case was "fact sensitive" and did not mean that future extradition requests from Argentina would necessarily be turned away.

There was no attempt by the Argentinean authorities to challenge Dr Verdu's evidence of conditions in the country's jails and the judge said his decision may have been different had Argentina put forward evidence or given guarantees that Wright would not be mistreated.

No such guarantees had been forthcoming, the judge added.

Alun Jones QC, for Wright, of Tooley Street, London, SE1, earlier said degrading treatment and attacks on human dignity are "the rule" in Argentina's female prisons.

Wright, the court heard, was caught trying to smuggle over 6kg of cocaine through the capital city's Ezeiza Airport concealed in her luggage in March 2007, later skipping bail and returning to the UK via Brazil.

She was only in Argentina for a few hours, in transit from Peru, before she was stopped while trying to board an Air France jet to London.

In his ruling today, Mr Justice Silber, sitting with Sir John Thomas, said Wright "has stated that she admits she would plead guilty to a charge of attempting to import coctaine in the United Kingdom" and the Crown Prosecution Service is now free to charge her.