The UK’s foreign office recently launched an information campaign warning people of the dangers of ending up in a Spanish jail on drugs charges.
Among the campaign materials was a video with the shocking story of Terry Daniels, who was accused of smuggling a million pounds (€1.2 million) worth of cocaine from Brazil to Spain in 1997.
Daniels served 19 months of her sentence in the "tough" Topas prison, near Salamanca before being granted permission to serve out what remained of her reduced sentence in the UK.
This move was made possible by the 1983 Convention on the Transfer of Sentenced Persons, which lets prisoners request a transfer but doesn't guarantee the move. US prisoners can also be transferred home under similar arrangements.
But Daniels case was relatively rare — many US and UK prisoners in Spain's jails stay put.
There were 111 British prisoners and 52 US prisoners serving out their jail sentences in Spanish prisons in December 2012, excluding Catalonia, figures from the Spanish Prisons Authority (SGIP) show.
These figures for the two groups have remained relatively stable in recent years.
However, only 25 British prisoners were transferred back to the UK in 2012. In 2011, this number was 22, and in 2010, it was 17.
For US prisoners, the figures are even lower. Just one inmate was transferred from Spain in both 2012 and 2011, while six made the move in 2010.
In terms of conditions in Spanish jails, a spokesman for British charity Prisoners Abroad said these “vary greatly from prison to prison”. But it added Spain's prison system has one of the highest overcrowding levels in Europe.
Spain's general prison occupation rate is 91.8 prisoners by 100 places, while in the region of Catalonia that rate is a much higher 120.6, a 2013 Council of Europe report reveals. This compares to 96.6 percent occupancy in the UK.
But in May, Spain's Basque region touted plans to build a prison with plasma televisions in each cell and an indoor swimming pool.
And Spain also boasts prisons the 'five-star' Aranjuez jail with family cells where children can live with their jailed parents until the age of 3.
US Consular Agent for the US State Department for Western Andalusia is positive about the prisons she visited.
"Spanish prisons are amazing compared to US prisons", Maritheresa Frain, US Consular Agent for the US State Department for Western Andalusia told The Local.
"They are very liberal. The prisoners can wear regular street clothes and do art and language classes.
"One person I was visiting was even doing classes through Spain's distance learning university (UNED)".
Frain also says the administrators at the prisons she visits are very open.
Most of the prisoners she sees are in on drug charges and would never consider transferring to a US prison. "The crimes committed by the men I visit are drugs-related and therefore federal, and that would see them serving time in a federal prison in the US — something they don't want."
The US Consular Agent said she personally had only met one woman had taken the option to return to the US, and this had been for family reasons.
But Frain pointed out that there were now fewer US prisoners in Spanish jails after rules changes saw non-EU citizens in Spain convicted for less than six months being expelled from the country rather than incarcerated.
And a recent report in Spain's El País newspaper said many US prisoners may not be aware of transfer arrangements between Spain and the UK, which may also lower transfer numbers.
There were a total of 68,597 prisoners in Spanish jails at the end of 2012, ACAIP figures show.
Of this number, 22,893 — or 33.37 percent — were foreigners.
Numbers for 2012 were down 5.1 percent on 2008 numbers, mainly due to fewer foreign prisoners, SGIP reported.
Prisoners Abroad, which is currently helping 93 British citizens imprisoned in Spain, said there were various reasons prisoners may choose to stay in Spain.
“People need to balance up the length of their sentence and the time of the transfer process to see whether this is worth doing,” a Prisoners Abroad spokesperson told the Local.
“Prisoners can only apply for repatriation once they are sentenced,” and the transfer process can take 18 months to two years,” the spokesperson said.
“You can also be on remand for two years, or possible more in some cases, so this adds to the potential delay in returning home.”
Spain has tough penalties for drug charges including prison sentences of up to 20 years for hard drugs and as long as 6 years and 9 months for soft drugs.