The members of the group have told the AJ that they refuse to accept the EU could simply abandon the investigation, which was attempting to uncover wrong-doing in the appointment of architects RMJM and Enric Miralles and contractor Bovis ( European inquiry into Scottish Parliament to be called off)
The decision to abandon the investigation into the vastly over-budget project looked to have saved many red faces around the Holyrood complex. It also seemed to have spared the prospect of a hefty fine.
Although the UK had conceded that European competition rules were broken, the European Commission decided that an 18-month inquiry was to be dropped without further action.
The EC commented last March that it suspected the tender procedure had 'violated European rules on public procurement'.
The commission's decision not to push on with the investigation appeared at the time to represent the last chapter in the troubled history of the Stirling Prize winner.
Over the course of its difficult construction period, costs jumped from an estimated £40 million to £431 million and the building was delayed by more than two years.