The merger of Dibb Lupton Broomhead and Alsop Wilkinson was expected to be officially announced in the next few days after going to partners' vote on Sunday.
The new practice will be called Dibb Lupton Alsop, according to documents seen by The Lawyer. Public relations company Lowe Bell will handle publicity for the merger, the documents said.
Sources in Manchester report the alliance is already seen as a fait accompli with partners from both firms meeting up for a celebratory party last week.
It also emerged that Alsops had earlier approached Pinsent Curtis with similar alliance proposals before the start of negotiations with Dibbs.
But the Pinsents side rejected the idea because it saw no obvious benefits, say industry sources.
Pinsents senior partner Julian Tonks refused to comment on speculation, beyond saying that both firms are members of the Legal Resources Group, "and so talk about all sorts of things from time to time.".
The five regional firms of the LRG pool training resources and an office in Brussels.
Meanwhile, rumours surfaced last week of a tripartite marriage between Denton Hall, McKenna & Co and Cameron Markby Hewitt. The firms are said to be in talks.
Denton Hall's Jonathan Tatten said: "As part of our management process, we keep opportunities to develop the practice under regular review. It is not our practice to comment on rumours."
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