Five police forces, including Devon and Cornwall Police, are being taken to employment tribunals after hundreds of officers were "forced" out of their jobs after 30 years, it has been confirmed.
Under regulation A19, officers below chief officer rank with 30 years' service can be made to retire.
The Western Morning News reported last year how around 90 former officers, backed by the Police Federation, had lodged claims at employment tribunals.
Hundreds of officers were required to leave under the rule.
Yesterday, it was confirmed that Nottinghamshire would now join Devon and Cornwall, North Wales, South Wales and West Midlands police forces in being taken to tribunal.
Chairman of the Nottinghamshire police federation Phill Matthews said a small number of test cases will be heard, starting on February 11.
A total of 153 officers from the force were made redundant under the rule, and a similar number from Devon and Cornwall.
He said: "This is a wholesale, indiscriminate way of making large swathes of the workforce redundant with no compensation other than their pension, which they are entitled to anyway, to fall back on. This is age discrimination.
"We're saying that the force has used the regulation to balance its books rather than for the individual efficiencies that it was designed for."
He said that because police officers are classed as crown servants they cannot be made redundant.
A Nottinghamshire Police spokesman said: "We can confirm we are one of the five forces involved in the tribunal.
"We understand it is due to start on Monday, February 11, and we are going to be robustly contesting it."