When SJ Berwin elected Stephen Kon as its senior partner last year, it did so on a manifesto promise of international growth. And Kon has certainly delivered. The firm has never been one to follow the herd, and the successful conclusion of its merger talks with Sino-Australian giant King & Wood Mallesons (KWM) this week certainly marks it out. 

The combination – uniting the top 30 firm with the partnerships of legacy King & Wood and Australia's Mallesons Stephen Jaques – will create a firm of some 2,700 lawyers, with the UK firm's moniker being subsumed and KWM lawyers outnumbering SJ Berwin's five to one.

For many years the UK firm was an obvious candidate for a US tie-up, with its strong funds practice proving a lure, most notably in recent years for Proskauer Rose. But while a US deal may have proved elusive, with the draw of such a union ebbing somewhat with the loss of some key partners and profits per equity partner (PEP) on a downwards trajectory (dropping almost a third in five years), the KWM deal provides what many of SJ Berwin's rivals cannot claim – namely a genuine pan-Asia Pacific presence.

Clearly, bedding down such a deal will be quite a challenge, and, with KWM itself such a new business, the strength of SJ Berwin's partnership – long viewed as 'sharp elbowed' and 'insecure' – will certainly be put to the test.

When the tie-up goes live in November, SJ Berwin will join the growing ranks of firms using – or being forced by – the downturn to significantly remodel their practice. With merger activity driving revenues at the top 50 firms this year to £13.5bn, the typically conservative legal profession has undergone rapid change over 2012-13.

Twelve of the top 50 have carried out a merger in the last year (and some more than one) and, although several of these have been with smaller bolt-on practices, some – such as Herbert Smith Freehills – are transformative. If the initial post-Lehman years saw aloof City firms sit back and watch as the national market consolidated, they have now undoubtedly bought into the philosophy.

With the annual 'cautious optimism' of law firm leaders yet to play out in the deal market, the still faltering economy continues to divide the profession. This year eight firms saw PEP jump by double figures, while 11 have posted similar figures, but in decline. And while last year five firms saw dips in revenue, that number has doubled this year.

Alongside the merger-driven growth of several key players is the strong recessionary performance of firms such as Irwin Mitchell and RPC, both looking to expand away from a core insurance focus, while flashy firms such as Mishcon de Reya are rocketing up on the inside. 

One thing is clear from recent years – standing still is not an option.