After an Engineering degree Warren spent 30 years in the semiconductor industry becoming CEO at ARM in 2001 until 2013.

He was appointed CEO at Rolls-Royce in 2015 with a mission to modernise. He stepped down at the end of 2022, leaving Rolls-Royce with significantly increased capacity and platform for enhanced profitability and cash as the sector recovered post-Covid19, together with a clear path to decarbonisation of the product portfolio. 

Since 2007 he has served on the boards of several major engineering and technology companies, including De La Rue, BT, Dyson and Micron. Currently he is a non-executive director at ASML NV and Tokamak Energy Ltd., and Chair of NATS, and past President of the IET. 

He received a CBE in 2014 and a Knighthood in 2025.