Buckingham Group Contracting Ltd

British Government Departments

Canary Wharf Contractors Ltd

Carillion plc

Costain Group PLC

EMTEC Group Ltd

G4S plc

Galliford Try plc

GlaxoSmithKline plc

HETCo

ISG plc

Kier Group plc

Laing O'Rourke

Land Securities Group PLC

Lend Lease Group

London Underground Ltd

Mace Group Ltd

Morgan Sindall Group plc

Overbury

Sir Robert McAlpine Ltd

Skanska UK Plc

Transport for London

United House Group Ltd

Vinci PLC

Walter Lilly & Co Ltd

The Wates Group Ltd