Workers from RAF Cosford in Shropshire will join MoD workers from around the UK in a candlelit vigil in Whitehall over the privatisation of jobs. The national demonstration outside the MoD headquarters is to protest at planned changes to the future of training in the armed forces.
A major defence training centre, bringing up to 2,000 jobs, is planned for Cosford or at St Athan in Wales.
But the Public and Commercial Services Union said standards will be reduced.
Paul Barnsley, from the union, said: "These plans put at risk the future quality of the training of our armed forces.
"The unquenchable thirst for profit that will result will lead to a drop in standards and quality to ensure shareholder dividends."