Ashurst Morris Crisp is staking a claim in the US market by opening an office in New York.
The firm intends to launch the office at the end of the month.
It will be headed by corporate partner Alastair MacPherson with support from senior corporate associate Anthony Clare.
The firm boasts a number of major US clients and recently acted for US-based Profit Recovery Group International on its multi-million pound acquisition of Meridian VAT Group.
Commenting on the New York move, Ian Nisse, managing partner at Ashursts, says that the office will only practicse UK law.
He says: "We have got an increasing amount of US business. We need people to work closely with our clients and contacts."
In June, The Lawyer reported that the firm had engaged the services of management consultancy Hildebrandt International in a bid to find a suitable merger or alliance partner in the US, but Nisse says of the move: "It has got nothing to do with [a merger]."
Andrew Wingfield, the managing partner at Simmons & Simmons' office in New York, says: "[Ashursts] will not be seen as a competitor to New York firms already out there."
However, City sources remain unconvinced about Ashursts' expansion.
One City lawyer says: "I'm not sure there is enough room for another English firm out there.
"It could act as a representative office for London."
Another source says: "I had understood that the firm was concentrating on its UK and western European expansion. I'm not sure it would offer a great deal.
"It could be like being in Tokyo, where UK lawyers cannot practise local law but it is helpful for business to be where the clients are."
A US-based lawyer says: "It is no big deal.
"I imagine they would open a representative office to beat their bush around the American firms."
But he adds: "Clients do not choose a firm because they have a rep office, they choose it because they have a good office in London."