Campaigners launched legal action today in an attempt to ban the export from Britain of an anaesthetic used to execute prisoners in the United States.
Solicitors Leigh Day & Co and human rights group Reprieve will file a judicial review in a bid to stop the execution of US death row prisoner Edmund Zagorski, 55, who was sentenced for killing two men over a drug deal in 1983.
Arizona executed Jeffrey Landrigan for a 1989 murder last week despite a US shortage of the anaesthetic normally used, sodium thiopental, one of three components of the lethal injection.
The US state said it had to obtain sodium thiopental from a foreign source after this was cleared for use in the execution by the US Supreme Court.
After the execution, the Arizona attorney general's office said the drug used came from a British manufacturer but would not name the firm.
Reprieve said lawyers for Zagorski believed the US state of Tennessee - where he faces execution on January 11 - was seeking to buy the drug for use in executions, and this may be imported from the UK.
The group said Business Secretary Vince Cable had refused a request to issue an emergency order regulating the export of the drug.
Richard Stein, partner at Leigh Day & Co solicitors, said: "It is most disappointing that although Vince Cable says he and his Government oppose the death penalty, he is unwilling to take this small step which could save the life of Mr Zagorski and others. We will be asking the court to force him to act."
A spokesman for the Department for Business, Innovation and Skills, said: "We have investigated concerns that a UK company supplied sodium thiopental to the US for the use in the execution process.
"This drug is an anaesthetic with a legitimate medical use. As such, it is not subject to export controls.
"The British Embassy in Washington is raising our concerns about the possible use of a British manufactured drug in the US execution process.
"EU law prohibits exporting equipment which has a sole purpose in facilitating the application of the death penalty.
"As sodium thiopental has a number of legitimate uses - including in anaesthetics, medically induced comas and psychiatry - it is not subject to this law."