Linda Carty is convicted of murdering her 25-year-old neighbour
A British prisoner on death row in Texas has lost her latest legal appeal, which means she could soon be executed by lethal injection.
Linda Carty, 50, was sentenced to death in 2002 for involvement in abducting and killing a woman in Houston. She says she was framed.
The New Orleans fifth circuit court has opted not to overturn that verdict.
Her lawyers say Carty could die as early as next summer unless there is an appeal at the US Supreme Court.
Carty has British dependent territory citizenship because she was born on the island of St Kitts, in the Caribbean, to Anguillan parents.
The Foreign Office said it had made a number of representations on her behalf to the US government.
Earlier this year, it intervened in the legal process, filing an amicus brief to the US Appeals Court complaining of lack of notification of the woman's original arrest in 2001 and "ineffective counsel".
Last week a recorded plea by Carty was played aloud on the fourth plinth in London's Trafalgar Square.
In the interview, given from the Mountain View Unit in Texas, where she is awaiting execution, Carty said: "Texas doesn't care about clearing my name.
"It is going to have to come down to either the British government, a Member of Parliament or a US Senator."
Asked if she thought Prime Minister Gordon Brown could exert more pressure on the US over her plight, she replied: "He has to. You cannot sit passively by and, because you have a good relationship with the US, say 'I don't want to rock the boat'.
"You are talking about someone's life here."
She added: "He has to get up and say 'I am not going to allow you to kill this lady'."
Carty was convicted in connection to the kidnap and murder of Joana Rodriguez, who was seized with her four-day-old son by three men on 16 May 2001.
But she says she was framed by three men in revenge for her work as an informant with a Drug Enforcement Agency.