Thorough preparation is the key to selecting a consultancy successfully. The industry is unregulated so anybody can call themselves a management consultant. Most speak the same sales language and appear to offer similar solutions. Clients are left to balance large against small, generalists against specialists, local against international and advisers against implementers and outsourcers. There is no single model that fits all work.

"Choosing a consultancy is a tricky business," says Hugh Stafford-Smith, managing director of Maconomy, a business software provider. "You can't take a consultancy for a test drive and there's no 28-day return policy if you don't like what you've bought!"