2.27 The 1996 Business Case for the project envisaged that the PFI would be the most appropriate method of procurement for Airwave, subject to tests of affordability and value for money once the procurement was underway. Also expressed was the view that the public sector would be highly unlikely to have the skills and resources needed for such a risky project, and so PITO took the decision not to prepare a public sector comparator. By February 1999, however, PITO considered that a comparator would supplement the should-cost model in the assessment of the value for money of O2's offer. The first version of the comparator was available in early April and a working version was completed in September 1999, when negotiations with O2 were at an advanced stage.