The Doughnut was already too small for the number of GCHQ staff at its completion , as a vast expansion in the number of employees had occurred as a consequence of the September 11 attacks in 2001 . The staff numbered almost 6,500 by 2008 . The addition of a two-storey office block and a three-storey car park to the Doughnut was proposed in 2008 , but eventually suspended in 2011 . The new buildings were intended to facilitate the arrival of 800 staff from GCHQ 's former site at Oakley . Though it was initially felt that the Doughnut would be adequate for the new staff , 600 contractors working on technical projects for GCHQ were eventually relocated in a secret undisclosed building in the ' Gloucestershire area ' . The parking of cars by GCHQ staff on residential roads has caused ' annoyance ' among local residents in Benhall . It was believed that the arrival of new staff may have further affected local parking but GCHQ stated the presence of the new employees would have been offset by redundancies
September 11 attacks
September 11 attacks
The Doughnut