Lawyers for Pike filed an emergency motion to the Tennessee supreme court after the second pentobarbital dose was administered asking to halt and stay the execution, saying she was in “unnecessary agony”, and that the state was violating her right to be executed free of cruel and unusual punishment.

In a later statement, they said: “Tonight the State of Tennessee once again failed to carry out a lawful execution.

“We take no pleasure in being right, but the concerns raised by Ms Pike proved to be true: difficult vein access, blown veins, degraded pentobarbital, no emergency medical care available when things inevitably go wrong, all under a protocol that remains veiled in secrecy,” the statement said.

“Christa is being treated at a nearby hospital. We have not been informed as to her condition.”