The head of Deloitte, the world's second-biggest accounting firm, has predicted it could transform itself into a single global partnership during the next 10 years.

William Parrett, global chief executive of Deloitte, said regulators were likely to push the top accounting firms into becoming single partnerships, and that clients and investors might support what would be an enormous change to existing structures.

Deloitte will tomorrow publish its strategy for the next decade. It will warn its partners to be prepared to adopt new business structures.

If the big accounting firms were to become single global partnerships, their leaders would be able to exercise greater authority to drive up standards of audit work.

However, laws in many countries currently prohibit accounting firms from organising themselves as single partnerships. Instead, the firms consist of networks of member partnerships that are formed in the countries in which they operate.

The partnerships enjoy considerable autonomy. Regulators are increasingly questioning whether the federation-style structures can deliver consistent audit work across countries.

Mr Parrett, chief executive of Deloitte Touche Tohmatsu, the firm's global umbrella organisation, said: "My expectation, both from a business standpoint and a regulatory standpoint, is [ that] larger firms will evolve to a global partnership over the next decade."

Deloitte's 10-year strategy plan says its vision is "to be the standard of excellence", and will involve raising audit quality.

Deloitte's annual report, also released tomorrow, says its global revenues increased 10.9 per cent to $18.2 billion (€15.2 billion) in the fiscal year ending May 31st, 2005. Audit revenues rose 17 per cent to $8.7 billion.

Consulting revenues rose 8.5 per cent to $4.3 billion, tax by 1.3 per cent to $3.9 billion, and financial advisory by 9.8 per cent to $1.3 billion.