The attempted kidnap happened outside HMP Forest Bank in Agecroft at around 10:30am on Tuesday 29th October.
Four masked men in a car pulled in front of the private hire vehicle as it left the prison and headed back into Manchester along Agecroft Road.
Two of the men then got out carrying shotguns and walked over to the taxi to check the identity of the occupants, two prison staff members and a 'high-risk' ex offender who was being escorted to a half-way house.
After confirming the identity of the former prisoner inside they walked back to their vehicle and left the scene. It is thought that it was not the target they were looking for.
Prison staff were immediately contacted to ensure that the real target was not scheduled to leave.
An investigation is now underway.
GMP have issued the following statement on the incident,
"At around 10.26am on the morning of (Tuesday 29 October 2019), police were called to reports of suspicious circumstances at HMP Forest Bank, Agecroft.
"Initial enquiries have established that four men – at least two of which were armed with guns – surrounded a vehicle as it left the premises.
"After approaching the vehicle, the men made off.
"No injuries were reported to police and no arrests have been made.
"Enquiries are ongoing."
Anyone with information should contact police on 101, quoting incident 789 of 29/10/19. Reports can also be made anonymously to the independent charity Crimestoppers on 0800 555 111.