GCHQ tested the market extensively to judge the level of interest in the project

2.5  GCHQ advertised the project in June 1997 and received 149 expressions of interest. This response indicated that the PFI route for new accommodation was feasible and that there was sufficient market interest for it to hold a meaningful competition. GCHQ held a Briefing Day on 4th July 1997 so that the interested parties could obtain more detailed information on its requirements.

2.6  Following the Briefing Day, GCHQ received 18 Requests for Qualification, many from amalgamations of organisations that had attended the briefing. All four eventual bidders confirmed that there had been a great deal of interest from industry in the project, and praised the way GCHQ had initially sought this.