Stirk was previously a partner in the social media consultancy Rebel Alliance, which worked with clients including UKTV, The Observer and Random House.
Before that, he was a content planner at Wieden & Kennedy, where he oversaw the strategy for the award-winning "Nike5" campaign, as well as the "somebody else's phone" activity for Nokia.
Stirk was also the planning director at the digital agency Holler, where he was responsible for the IPA Effectiveness gold-winning campaign for the launch of E4's Skins. He was also the managing director of TBWA\London's Upstart division, which launched in 2004 to work with clients with smaller budgets.
His appointment completes the BETC London management line-up as it launched without a planning head.