A prisoner was released from jail in error after he was confused for another inmate who has the same surname.
Anthony Douglas, in his 20s, walked out the doors of HMP Hewell in Worcestershire on Wednesday after he was mistaken for another prisoner who was due for release.
He was arrested the next day and returned to the prison.
How the Burton-on-Trent man managed to be freed in such a blunder is now the subject of an internal investigation.
The spokesman for The Prison Service said: “The police were notified immediately and he was recaptured on 3 July.
“An investigation by a senior governor has been launched.
“We take public protection extremely seriously and this type of incident is a very rare but regrettable occurrence.”
It is unclear how long Douglas had left on his sentence or what he had been jailed for.
A senior member of staff has been suspended, according to the Birmingham Mail, with the mix-up coming just eight months after convicted murderer Alan Giles escaped from the same prison.
HMP Hewell was created in 2008 to serve the Worcestershire, West Midlands and Warwickshire areas with a capacity of 1,261.
The highest category of prisoner the jail can house is Category B – convicts who do not need to be held in the highest security conditions, but for whom the potential of escape should be made very difficult, guidelines state.