Shell has slashed its legal panel from eleven firms to just six advisers the oil giant announced today.

The company's revised main roster, the first since its merger with rival BG Group earlier this year, is accompanied by 12 regional panels with up to five firms on each.

Magic circle firms Allen & Overy (A&O) and Clifford Chance (CC) have both secured coveted places on the panel alongside Eversheds, Norton Rose Fulbright, Baker & McKenzie and Reed Smith.

The six month review process was led by Canada-based associate general counsel for disputes, strategy and coordination Gordon McCue.

McCue reviewed over 200 firms in order to reach the final six. The panel will be in place for four years with rates being reviewed in May 2018.

Shell legal director Donny Ching said: "The new firms bring with them a combination of strong legal experience and expertise, global reach, and flexibility with regards to cost arrangements that will help Shell achieve a higher standard of performance for our organisation, maintaining a strong and growing long-term position in the competitive environments in which we operate."

Shell last reviewed its panel in 2013, handing roles on the 11-strong roster to Allen & Overy, Baker & McKenzie, Clifford Chance, Norton Rose and Simmons & Simmons among others.

Each of the six panel firms on the new roster has been appointed a "relationship general counsel" who is one of Shell's eight divisional general counsel.

Shell has retained the ability to invite off-panel firms to pitch for specific pieces of work.

A Shell spokesperson said: "Shell operates in 70 countries around the world so we are going to retain the flexibility to engage with the right lawyers in the right time with the right issue."

Firms were asked to participate in an online rate auction, despite the company moving away from an hourly fee structure to alternative fee arrangements.