[6]  In 2013, Astex was acquired for around USD $900 million[7] and now operates as a wholly owned subsidiary of Otsuka Pharmaceutical Co. Ltd, headquartered in Tokyo, Japan.

He is one of the few industrial scientists to have served as President of its Organic Division (2010-2013), and was later elected to the RSC Board of Trustees (2015-2019).

[12] Rees has held visiting professorships at three UK universities, and sits on several scientific advisory boards for not-for-profit organisations.

In 2020 he was elected as a Fellow of the Academy of Medical Sciences and inducted into the RSC BMCS Hall of Fame.

Rees is also a Director of Ashanti Development, a charity that promotes clean water and sanitation in Ghana.