Prison officers have rejected the coalition government's pensions plan in a ballot of union members.
POA, the union representing 35,000 Uniformed Prison Grades and staff working within the field of Secure Forensic Psychiatric Care, said the result was "overwhelming".
It rejected plans to link to normal pension age and the state pension, which would mean prison officers working until 68.
Peter McParlin National, Chairman of the POA, said:
"The ballot result is clear and unambiguous. The POA will not allow politicians to compromise the health and safety of our members and the prisoners and patients in our care.
"A pensionable age of 68 is inappropriate within essential and uniformed services.
"The POA will continue to exert pressure on the coalition government to revisit their disgraceful pension imposition".
88.5% of union members rejected the changes to the Principal Civil Service Pension Scheme (PCSPS) in a postal consultative ballot of members in England and Wales, Scotland and Northern Ireland.
The turnout was 28.7%.
The Treasury's discussions with health, education and civil service unions on details for new public service pension schemes finished earlier this year.
In April 2015 the current Civil Service pension schemes will move to a new career average scheme for the majority of civil servants from April 2015.
The POA said it is working with other unions on the '68 is too late' campaign to oppose the increase in the state pension age to 68, and the threat that the Government will move it even higher.
Steve Gillan General Secretary of the POA said:
"This is a massive rejection of pension changes by a loyal hard working workforce who protect the general public. I do not believe the general public will want to see prison officers being forced to work until 68 years of age. The POA will continue to campaign for fairness and will not rule out further action".