Her solicitor Carl Richmond said: "I got the feeling there had to be a scapegoat because there was absolute chaos at the hospital and it could not function because of all the speculation. I was imploring the police to bail her while they continued their inquiries but the decision was made to charge. They jumped the gun, though, and tried to build the case against her from there rather than the usual method of bailing her pending further inquiries."

He said he had heard rumours that prosecutors involved in the case were not comfortable with charges being laid against her but ultimately the Crown Prosecution Service decided it thought there was enough evidence against his client.

Mr Richmond said no decision had been made yet to sue police for wrongful arrest but Ms Leighton, her family and her legal team would meet as soon as possible to discuss the matter.

During a bail application last month, it emerged the evidence at that stage against the nurse amounted to her fingerprint being on a saline bag which was damaged by a needle. Her thumb print was also discovered on the bottom of a bottle of antibiotic fluid which contained insulin.

A judge at Manchester Crown Court was told, though, that "many people" had access to both the bag and the fluid, and Ms Leighton had reason to touch them in her role as acting sister.