In the video above, Thornton said Bailes personally "tapped the winning ball over the line" with O2's "be more dog", which picked up Campaign of the Year in The Annual 2013.
Bailes is currently off work after breaking his leg.
Thornton said. "This is his day. What the agency has achieved today is in recognition of his development of the agency".
Sophie Maunder-Allan, the group strategy officer at VCCP, said both client and agency had made a "bold, brave move" with the campaign, highlighting that "real collaboration between an agency and the client works best".
VCCP also won the Advertising Agency of the Year accolade in last week’s Campaign Annual.