Lindsay Sandiford could seek a judicial review if Indonesia's Supreme Court rejects her latest death penalty appeal, human rights campaigners have said.
However, such a move would largely depend on whether new evidence had come to light, they added.
After that, her final resort would be to seek a reprieve granted by the country's president.
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TV presenter Helen Skelton is a supporter of the campaign and is calling for more parents to get out on their bikes with their children.
Mrs Justice Nicola Davies will sentence Berlinah Wallace, 48, at Bristol Crown Court.
The JR4NHS group was founded by three doctors and a university professor, and supported by the renowned physicist until his death in March.