SINCE City A.M.’s last awards ceremony in 2011, the legal sector has undergone one of the biggest shake-ups in recent years with the introduction of the Legal Services Act.

The introduction of Alternative Business Structures (ABS) on 3 January was a formal acknowledgment of the ripples of change that have been spreading across the legal sector for a while – until recently one of the most closed and traditional industries in corporate Britain.

It has seen high street challengers such as Co-op vowing to take on the market by expanding the services it offers in branches, leaving many firms reassessing their futures and looking to global consolidation to drive stable growth.

Meanwhile, the main corporate firms are still battling for places on the City’s biggest deals, joining bankers in hoping that a pipeline of M&A or public listings might pick up again soon.

Against such a tumultuous backdrop, several firms have stood out – either for their innovative routes to expansion, or for their consistent mandates for the financial world’s most influential players, both at home and abroad.

Clifford Chance
Managing partner: David Childs
The Magic Circle stalwart is always nestled near the top of M&A advisory tables, and has continued to dominate over the past 12 months despite an ongoing lack of pipeline deals. Since last year’s awards it has advised Pfizer on the sale of its nutrition business to Nestlé, Citigroup on its disposals of EMI’s music and publishing businesses, and RBS on the sale of its aircraft leasing business for $7.3bn. The firm’s regulatory team has also continued to shine, shaping the future of financial law by advising watchdogs around the world.

Herbert Smith
Managing partner: David Willis
In a year that saw many law firms forging international brand tie-ups but keeping the money pots separate, Herbert Smith bucked the trend through its full equity merger with Australia’s Freehills. If all goes to plan, the firm, which will share a profit pool and be one of the world’s top 10 firms by headcount, will go live before our awards ceremony in October. Its 2,800-strong team of lawyers will, according to Freehills boss Gavin Bell, “give Herbert Smith Freehills the platform to become the leading global law firm across Asia Pacific”.

Allen & Overy
Managing partner: Wim Dejonghe
Always well-lauded for its corporate and finance work, A&O kept up the momentum this year by finding bright spots among ongoing economic crises. Derivatives partner David Benton enjoyed a spell in the Eurozone spotlight as he advised Greek bondholders, including BNPP, Deutsche Bank and HSBC, on the country’s controversial debt restructuring. Meanwhile the corporate team was kept busy on one of the most politically complex M&A deals in recent years – helping Virgin Money buy Northern Rock from the Treasury.

Managing partner: Simon Davies
Linklaters was another City firm looking further afield this year, launching an alliance with Australia’s Allens to boost its energy, resources and infrastructure work in the region. But it also excelled at home on some of 2012’s biggest M&A deals – helping long-term telecoms client Vodafone on its successful £1bn bid for Cable & Wireless Worldwide, and leading for Glencore on its merger with Xstrata, having helped to negotiate the commodities giant’s entrance onto the London markets last year.

Norton Rose
Chief executive: Peter Martyr
Norton Rose reaped the benefits of its acquisition spree this year, seeing impressive growth as results from its Canadian and South African tie-ups were included in global figures for the first time. From its headquarters south of the river, the firm has also made sure its domestic practice is at the forefront of its sector specialisms, including advising the Malaysian buyers of Battersea Power Station, and putting together a team of banking dispute and anti-corruption specialists to steer ex-Barclays boss Bob Diamond through the Libor scandal.