A British woman who has been on death row in Texas for 14 years has been given renewed hope that she might be spared execution by an appeal hearing at which devastating evidence was presented that prosecutors had coerced false testimony from key witnesses.

Linda Carty, 57, has a high profile in Texas as one of just six women facing execution in the state and as a British citizen by dint of her birth in St Kitts at a time when the Caribbean island was still a British colony. Her case has been highlighted in documentaries and championed by the likes of Bianca Jagger and the British government.

Carty has always protested her innocence on charges that in 2001 she commissioned three men to carry out the kidnapping and murder of her neighbour, Joana Rodriguez, in a plot to steal the victim’s three-day old baby. Previous attempts to appeal her death sentence have failed, despite the absence of any forensic evidence against her and the fact that she was represented at trial by a defense lawyer who spent only two weeks preparing the case.

Close observers say that this week’s hearing before a single judge appointed by the Texas court of criminal appeals takes her plea of innocence to another level. The hearing, that is likely to be concluded with the judge’s opinion in early September, presents her with the greatest hope yet that she might secure a retrial.

Michael Goldberg of the law firm Baker Botts, who has been Carty’s lawyer for the past 13 years, said that it was highly unusual that his client had even reached the stage of a post-conviction evidentiary hearing. “We were very happy when the court of criminal appeals granted us this hearing, since it rarely does in Texas,” he said.

Goldberg added that “now that we’ve concluded the hearing, the evidence that we were able to present shows even more conclusively that Linda’s rights in the first trial were abused and that a new trial is required”.

During this week’s hearing, Goldberg spent eight hours cross-examining Connie Spence, the lead prosecutor in the case who still works as a supervisor for the Harris County district attorney’s office in Houston. Part of that cross-examination related to the explosive affidavit given in 2014 by Charles Mathis, a former agent of the Drug Enforcement Administration (DEA).

In the affidavit, Mathis recounted how he had recruited Carty as a confidential informant who could provide useful information to the DEA on drug dealing in the city given her expertise as a trained pharmacist. He said that when he told Spence that he did not want to testify at trial against Carty, the prosecutor threatened to concoct a story about him having had an affair with the defendant.

“I was shocked when Spence said this … I felt Spence was threatening and blackmailing me into testifying,” he said.

The judge heard further allegations that the prosecutors had fabricated evidence, destroyed essential case notes and emails that might have helped the defense and withheld several recorded witness statements that should have been handed over to the defense team.

Both Spence and another prosecutor on the case who also still works for the DA’s office appeared at the hearing, and both denied that they had done anything to coerce evidence from any of the witnesses. According to a report of the hearing by the Houston Chronicle, Spence told the judge: “Defense had access to the evidence any time they wanted to look.”

Closing arguments in the appeal will be presented on 29 August, and the judge has indicated he will give his opinion within the first 10 days of September. Should the judge recommend a retrial, it will then be up to the full court of criminal appeals to decide whether or not to act upon his advice.