The firm has been bidding against Laing O’Rourke to deliver a £300m advanced hospital offering cutting-edge treatment at Stanford Hall stately home.
Sources have told the Enquirer that Interserve is expected to be revealed as the preferred bidder for the ambitious project near Loughborough shortly.
The firm previously built a smaller rehabiliation centre in Plymouth for British services charity Help for Heroes.
Designed by John Simpson Architects, the purpose-built Defence and National Rehabilitation Centre will be four-times the size of Headley Court in Surrey, which it will replace.
It will also provide rehabilitation facilities for the public, who for example may have been injured in car accidents.
The Government has given the green light and work is expected to start in mid-summer with the new facility due to become operational on the Stanford Hall estate in 2018.
Development of the centre at the 360-acre estate will be funded by donors led by the Duke of Westminster, who bought the stately home in 2011.
There will be a specific Complex Trauma unit, built to acute hospital medicine standards to treat and rehabilitate the most seriously injured.
This will offer 80 beds and be kitted out with a gymnasium, physiotherapy, hydrotherapy pool and advanced prosthetic workshops.
Another wing will act as Neurological Centre with 20 beds in ward accommodation, a gymnasium, physiotherapy and vocational therapy to treat and rehabilitate people with neurological injury. Rehabilitation will be progressive and may extend over many months, or years.