Fellow of the Royal Academy of Engineering

Fellowship of the Royal Academy of Engineering (FREng) is an award and fellowship for engineers who are recognised by the Royal Academy of Engineering as being the best and brightest engineers, inventors and technologists in the UK and from around the world to promote excellence in engineering and to enhance and support engineering research, policy formation, education and entrepreneurship and other activities that advance and enrich engineering in all its forms.
Fellowship is a significant honour. Up to 60 engineers are elected each year by their peers. Honorary and International Fellows are those who have made exceptional contributions to engineering.
The criteria for election are stated in the charter, statutes, and regulations document. The essential attributes of excellence in engineering 
include:
Fellows are entitled to use the post-nominal letters FREng; prior to the Royal Charter in 1983 FEng was used. 
See for examples of fellows.