North-west based law firm Weightmans is opening a London office in May next year.
It is recruiting the whole of the litigation group from London firm Vizard Oldham, made up of 16 partners and their teams.
The London office will be known as Weightman Vizards and is likely to be based in the Chancery Lane area.
Weightmans senior partner Ian Evans said Weightmans, which currently has offices in Liverpool, Manchester, Leicester and Birmingham, had been looking for an opportunity to expand into London for some time.
Vizard Oldham's staff will be augmented by people from existing Weightmans offices.
Evans added that, although it was early days for the merger, a number of staff had already enquired about transfers to London.
It is unclear at the moment what the future plans of the remainder of Vizard Oldham are. "That is something ongoing that has to be settled," he said.
The aim of the merger is to establish integrated national units in specific areas of expertise. There will be 70 partners nationally in the new firm.
"Our objective is to establish a wider presence in the healthcare, professional indemnity and employment sectors and national units to service public authorities," Evans said.
"This move will also enable us to provide greater strength and representation in general insurance and commercial litigation."
Senior partner at Vizard Oldham Richard Foster joins the new firm's national strategy board, with finance partner Mark Whittaker joining the national operations board.
Weightmans, which recently had failed merger talks with Newcastle firm Jacksons, has no immediate plans for further acquisitions.
Evans said with the Liverpool office moving to new premises, the Birmingham office outgrowing its space and the London merger, the firm had enough on its plate.