Norton Rose’s incoming chairman Stephen Parish has vowed to steer the firm towards a US merger, believing that a New York office is crucial for any ­international law firm.

Parish said the best way to gain a credible US presence would be via a future ­merger.

“Within a period of between five and 20 years I believe we’ll need to have New York and English law capability across a number of practice areas in which we work,” he said. “The most obvious way to achieve this is by way of a merger with a New York, or at least a North American, law firm.

“If you purport to be a genuinely international law firm you’ll have to offer both English and New York law capabilities. I think it’s inevitable that there’ll be mergers in due course.”

Admitting that there would be cultural issues to overcome before a ­transatlantic merger could work, Parish added that he believes there will be a ­gradual ;narrowing ;in ­profitability between New York and English law firms.

Parish, who is currently head of banking at the firm, takes over from current chairman Paul Giles at the beginning of May following a contested election, which saw him fend off competition from Middle East managing partner Campbell Steedman.