Toronto firm Fasken Campbell Godfrey and Montreal's Martineau Walker are merging in an attempt to rationalise Canada's fragmented legal network.
The firms' partners voted to form a 370-lawyer single practice - Fasken Martineau - last week. Faskens is also understood to be in talks with a Vancouver practice, and has set up a New York office.
Faskens' London partner John Elias says business from US-based clients is booming in Canada. Faskens and Martineaus have worked with each other for many years and have operated the joint London office for 13 years.
The mergers are a response to Canada's legal system, which is split into separate jurisdictions. "It is frustrating for international clients," says Elias.
"Our long-range strategy is to make sure we have a presence in all the major centres in Canada, and it is a factor that is making other firms examine their strategies."
Also last week, Ottawa's Gowling Strathy & Henderson merged with Calgary's Code Hunter to form a 450-lawyer firm. In October Toronto-based Tory Tory DesLauriers & Binnington joined with New York's Haythe & Curley.
Toronto's Osler Hoskin & Harcourt has closed its London office and relocated to Canada.