The POA appealed and the Court of Appeal reversed the judgment below on 4th December last year - Iqbal v POA  EWCA Civ 1312. The Court was worried that if prisoners were not let out of their cells by mistake or inefficiency, the Courts would be overwhelmed with claims:
"The rights of prisoners should certainly be acknowledged: indeed according and respecting rights are one of the hallmarks of a civilised society. Further, it can fairly be said that every moment out of his cell is valuable to a prisoner. However, I think that the court should be reluctant to reach a conclusion whose implications could lead to many small private law damages claims arising from what may often be little more than poor time-keeping by prison officers, and whose outcome may often turn on issues such as whether an officer in an undermanned prison could better have organised his working day to ensure that a prisoner was let out of his cell at precisely the time stipulated by the governor."
The MR would have awarded him £120 rather than £5 if he had have been falsely imprisoned.
But at least common sense prevailed in the end.