Terrett co-authored the UK Government Design Principles[1] which Tim O'Reilly called "the most significant since Apple's".

"[4] As of February 2019[update] he is the CEO of Public Digital and a Deputy Chair at University of the Arts London[5] Terrett was born in 1975.

In 1997 he won the Royal Society of Arts Student Design Awards prize for Interactive Graphics.

[15] Terrett has co-authored a book about his time in government: Digital Transformation at Scale: Why the Strategy Is Delivery.

He declined the Presidency citing the lack of diversity in similar industry roles[26] saying "I look around at the world and I see too many people who look like me, middle-aged white men, in positions like this, so I've decided to stand aside and make space for others."

[39][40] 12 March 2012 at SXSW in Austin Texas, Terrett spoke on a panel which introduced the concept The New Aesthetic organised by James Bridle and included Aaron Cope, Joanne McNeil and Russell Davies.

[44] 10 March 2014 Terrett spoke at the Bloomberg Businessweek Design conference in San Francisco, California.