The agency, which has since been shortlisted for the Government's £75 million anti-obesity task, is understood to have been frustrated by the creative potential afforded by the business since September 2006, when Whitbread, Pizza Hut's UK franchise partner, sold its 50 per cent stake back to its US parent Yum! Foods.
Hugh Wood, the Pizza Hut UK marketing director, will now hold a review of the business ahead of a relaunch that aims to position the brand away from its fast-food roots and towards casual dining in the style of chains such as Nando's.
He said: "We've enjoyed working with W&K over the past three years and we'll continue to do so over the next few months as we conduct a pitch process."
W&K won the Pizza Hut business from Abbott Mead Vickers BBDO in February 2005.