Partners at the law firms Charles Russell LLP and Speechly Bircham LLP have voted in favour of the companies merging.
Charles Russell Speechlys will have 500 lawyers, 170 of whom will be partners. It will open for business on November 1, 2014.
The firms said IP is one of several “significant strengths” that the new outfit will have.
Charles Russell Speechlys will be split into four main divisions: business services, litigation and dispute resolution, private client, and real estate and construction.
It will be headquartered in London, with offices in Europe and the Gulf.
Christopher Page, senior partner at Charles Russell, said: “The beauty of the new combination is that it gives us real scale—and the ability to invest—across our practice groups.”
“The real work starts now,” added James Carter, managing partner of Speechly Bircham. “Our integration team is tasked with finding the very best elements of both firms and making them work effectively together. It will also be looking at workflow, team combinations and optimal use of office accommodation.”