British diplomats have complained to the US government about a drug imported from the UK being used in the execution of death row prisoners.
Officials from the British embassy in Washington said they were "dismayed" and "very concerned" that UK-sourced sodium thiopental, a barbiturate injected to induce unconsciousness, would be used in future executions. They have also objected to its use in the execution of Jeffrey Landrigan, a death row prisoner who reportedly suffered from mental health problems.
In a letter sent to the Department of State, a copy of which has been obtained by The Independent, the British officials also warn that it would be illegal for the drug to be used again – such as in the planned execution of Edmund Zagorski in Tennessee – because the imported compound has not been officially approved for use by the Food and Drug Administration (FDA).
"As you know, the UK firmly opposes the death penalty in all circumstances as a matter of principle," states the letter, from the embassy's political counsellor, Ian Bond.
"I am aware that the UK and US governments do not see eye-to-eye on this. It is nonetheless deeply concerning to hear reports that US states may be importing sodium thiopental from the UK in order to put convicted persons to death.
"We were especially dismayed to hear about the execution of Jeffrey Landrigan in Arizona on 26 October, given reports that he suffered from severe mental health problems; the 9th US Circuit Court of Appeals had previously stayed his execution because of the lack of clarity about the provenance of the sodium thiopental to be used."
The diplomat adds: "We are also very concerned about the possibility of UK drugs being used in future executions in the US.
"Our understanding is that sodium thiopental sourced from the UK is not FDA-approved for use in the US. We would therefore be grateful for any steps the Federal Government can take to prevent it being used here."
Vince Cable, the Business Secretary, recently introduced restrictions on the export of the compound, with manufacturers now requiring a licence to ship it abroad. But some American states have already bought enough of the UK-sourced drug to go ahead with further executions, while others have refused to disclose their suppliers.
The only British manufacturer of the drug, Archimedes Pharma UK in Reading, denies providing it for the purpose of executions. US states have had to look abroad for a supplier because the only domestic manufacturer, Hospira, has run out – a raw material shortage means it will not have a new batch ready until early next year.
Last night, campaigners praised the strongly worded diplomatic letter, but said Britain needed to take further action to ensure British-sourced drugs already purchased by US states were not used to put more people to death.
"I was surprised and pleased to see such a robust approach from the British Government," said Clive Stafford Smith, the director of Reprieve, which campaigns against the death penalty. "We now need to see the Government take a much tougher stance with the British companies involved in the exports. It is not good enough for them to say that they simply sell the drugs and then wash their hands of what it is used for.
"It is illegal under FDA rules for US states to import sodium thiopental. We know for sure that Arizona bought four batches from Britain. Tennessee has already bought it, too. California has bought some and it is currently en route there."
Two other drugs used in the execution process have also been supplied by British companies, documents from California show, leading to calls for a total ban on the whole group of drugs used in lethal-injection procedures.
Pancuronium bromide, used to cause muscle paralysis, and potassium chloride, which stops the heart, have both been exported, according to documents obtained by Reprieve from the California Department of Corrections.
"I suspect one London-based company is buying these drugs and shipping them to the Americans," Mr Stafford Smith said.