It is still unclear whether the core £10 million Lucozade Energy account, which has been promoted heavily in conjuction with Lara Croft in the past, will also come under review.
The decision to invite outside agencies to pitch in the UK breaks with the policy GlaxoSmithKline adopts globally for Lucozade, which uses O&M as the lead agency in all markets that require an above-the-line agency. Grey Worldwide is its other key roster network.
Lucozade is part of GlaxoSmithKline's consumer healthcare division, which includes brands such as Horlicks and Ribena, both handled by Grey, as well as Aquafresh, Oxy and Panadol.
It is unknown if GlaxoSmithKline plans to review its Solstis drinks brand, which is also handled by O&M.
The review will come as a blow to O&M. It is currently fighting to retain its £18 million KFC account, which it has held since 1995, in an AAR-organised pitch against Bartle Bogle Hegarty, Abbott Mead Vickers BBDO and Clemmow Hornby Inge.
O&M has lost a number of major UK-based accounts this year, including the £30 million Argos work in May after a 13-year relationship. The loss is thought to have cost the agency more than £1 million in fees.
It also lost the £7 million Royal & Sun Alliance's insurance brand More Than, the £4 million account for Observer newspapers and The Samaritans business.
O&M and GlaxoSmith-Kline refused to comment as Campaign went to press.