Civil service union PCS has raised concerns about plans from the Ministry of Defence that could see more than 100 military base caretakers lose their jobs and homes.
PCS said the MoD has launched a four-week consultation on plans to remove all 125 caretakers roles in the Army Reserve and University Officers' Training Corps estate across England, Scotland, Wales and Northern Ireland.
The union said 88% of those potentially affected live in tied accommodation, meaning many long-serving staff could be forced to leave the homes they have lived in for years as a direct result of redundancy.
According to PCS, the consultation says the proposals support Strategic Defence Review commitments to reduce civil service workforce costs by 10% and headcount by 15%, with the MoD estimating net workforce savings of £12.5m over 10 years from the plans.
The union said military base caretakers provide a vital on-site presence that includes: responding to emergencies; securing military sites; supporting police and fire services; managing contractors and deliveries; maintaining health and safety compliance; opening facilities for reserve and cadet units; and, often, acting as the first point of contact when incidents occur outside normal working hours.
PCS general secretary Fran Heathcote said: "These proposals are devastating. Over 100 dedicated workers face losing not only their jobs but also the homes that come with them after years, often decades, of loyal service keeping sites safe, secure and operational. At a time when affordable housing is increasingly out of reach, expecting families to rebuild their lives within a matter of months is simply unacceptable."
Heathcote said the MoD's "own consultation acknowledges shortcomings in the contractor and digital systems that are expected to replace these roles, yet it is pressing ahead regardless".
She added that PCS "will oppose these proposals vigorously and continue to fight to protect both these vital jobs and the people who do them".
The MoD has been approached for comment.