Deloitte will this week report a 17 per cent jump in revenues over the past year, in a clear sign that the credit crunch has failed to dent the top end of the professional services market.

The industry, dominated by the “Big Four” of Deloitte, PwC, KPMG and Ernst & Young, is often considered a mirror for the broader business environment. The fortunes of the world’s four top auditors are closely linked to those of their clients, who represent the world’s biggest companies and industries.