Allen & Overy and Fieldfisher are among six firms that have been cut from National Grid's roster as it slims-down its panel from 17 to 12.

The magic circle firm has lost its position as one of National Grid's key corporate advisers. Walker Morris, BrookStreet Des Roches and Fieldfisher also lost out in the re-shuffle.

Legal Week understands two further firms previously on the panel no longer have a spot.

Herbert Smith Freehills, Irwin Mitchell and Addleshaw Goddard have been added to the utility provider's roster of full service firms, alongside incumbents Eversheds, Linklaters, CMS Cameron McKenna and DLA Piper.

Irwin Mitchell's appointment is a coup for the firm as it dropped off the panel last year amid a review of existing firms, having previously provided debt recovery work.

Norton Rose Fulbright is a new appointment to the panel, but will only provide specialist advice. Other firm's that retained their specialist spots include Dentons, Shakespeares Martineau, Berwin Leighton Paisner and Bircham Dyson Bell. These firms are all appointed to cover areas such as gas and electricity issues, property, planning and corporate services.

The panel will run for two years with an option to extend it by another two years.

National Grid kicked off the tender process in March and the panel is due to take effect in September.

National Grid's group general counsel Alison Kay (pictured) said that although there were now fewer firms on the panel National Grid had "greater coverage and focus".

"Our review of the panel aimed to deliver an agile and smarter service delivery model with firms closely aligned to our business needs.

"We plan to work with the firms in a closer way to ensure successful delivery and use operational excellence methods such as aligned objectives, closer management of the outcomes to be provided and two way secondments to provide deeper understanding".