Allen & Overy (A&O) has secured its first major instruction from Simmons & Simmons telecoms client One 2 One by advising on a major third generation (3G) network co-operation agreement.

One 2 One, part of the wireless division of Deutsche Telekom, has instructed A&O corporate partner Chris Watson for the first time since he joined the firm from Simmons two years ago. Watson regularly advised the client while at Simmons.