The agency is making public all potential bidders for its next generation contracts to allow subcontractors to approach firms hoping to win work on its giant spending programmes.

These have been reshaped into four regional prime contracts for facilities management, one national and six regional capital works frameworks for construction projects and a national housing prime contract.

It will also hold a series of industry days to spell out the big changes coming about from April 1 when the new single MoD body to be called Defence Infrastructure Organisation takes control of all procurement at the estate.

One of DIO’s chief remits is to extract £1.2bn in programme savings over the first four years, although the budget is under wraps.

First up is the regional prime contract for Scotland and Northern Ireland, which covers hard facilities management of projects valued under £3.93m.

The invitation to prequalify has attracted 30 firms, most from major league players hoping to move into the next stage of procurement.

Steve Rice, head of the NGEC programme, said: “During this period of significant change across Government, sound engagement and communication with industry are essential to the procurement process.

“I am determined that through these industry days we should be setting out our requirements clearly and openly, to ensure that potential bidders get the best possible chance to demonstrate their merits.

“We also want to support small and medium-sized enterprises in identifying and researching supply chain opportunities, and the online NGEC Potential Bidder Directory is one way in which we hope to achieve this.”

Procurement chiefs now plan to hold a bidders day on 24 March to spell out the bid changes being rolled out at the procurment body.

The event is Edinburgh is being kept by invitation only, but firms which have written during the prequal period to request places at specific industry days as potential subcontractors or supply chain members will also be invited to attend.

Further industry days are planned for each prime contract, and for each of the regional and national Capital Works Frameworks, although details have not been made public yet.

Defence Estates plans to shortlist between three and five firms for each regional prime and up to a dozen firms for each capital works framework, all will be invited to attend a second event spelling out details for bidding.