Sandiford, from Redcar in Teesside, has insisted she was set up and was forced by a gang to smuggle drugs to Bali to protect her children.
On hearing the sentence, Mrs Sandiford wept and declined to comment as she was led back to prison, covering her face with a scarf.
Martin Horwood, the MP for Mrs Sandiford's constituency of Cheltenham, said that he was "really shocked" at the sentence.
"We hadn't actually expected [the death penalty] in this case because the prosecutors themselves had only asked for a jail sentence," Mr Horwood said.
He added: "There are good judicial processes in Indonesia and we just need to take advantage of those."
On hearing the sentence, Mrs Sandiford wept and declined to comment as she was led back to prison, covering her face with a scarf.
Martin Horwood, the MP for Mrs Sandiford's constituency of Cheltenham, said that he was "really shocked" at the sentence.
"We hadn't actually expected [the death penalty] in this case because the prosecutors themselves had only asked for a jail sentence," Mr Horwood said.
He added: "There are good judicial processes in Indonesia and we just need to take advantage of those."