Alps (pictured) set up Thinkbox in 2006, and was previously chair of PHD Group for 13 years, including six years running its content division, Drum. 

Alps is a fellow of the Marketing Society, member of the British Academy of Film and Television Arts and a fellow of the Royal Television Society.

A spokesperson for Thinkbox said that it has not appointed a replacement for Alps.

Lindsey Clay, chief executive of Thinkbox, said: “This is obviously a sad moment for us, but also a wonderful excuse to shower praise upon a peerless person. No one has done more to champion TV, and advertising more widely. And no one has done so with more passion, integrity, conscience, wit, and success.

“I know I speak on behalf of everyone who has worked at Thinkbox and all our shareholders when I wish her the best in her well-earned and hard-won retirement. Tess is a one-off, a wonder and we’ve been incredibly lucky to keep hold of her for so long.”

Alps said: “It truly has been the honour of my life to be part of Thinkbox for the last 14 years. I only meant to stay for three, but TV has been in such an exciting and dynamic phase for all that time that it’s been hard to drag myself away.

“I’m proud that Thinkbox has been part of helping the marketing community fully appreciate its pre-eminent contribution to our cultural and commercial life, not just in the UK but globally. TV will continue to evolve and thrive and Thinkbox will be there to guide advertisers through.”