A co-investigator in the new Innovation and Knowledge Centre in Smart Infrastructure and Construction, Professor Middleton was one of four East of England engineers to be elected Fellow of the Institution (ICE). Fellow is the highest grade of membership of ICE and is awarded to members who are or have been engaged in a position of responsibility in the promotion, planning, design, construction, maintenance or management of important engineering work.

Professor Middleton's main research interests are in bridge engineering, in particular the ultimate strength of concrete structures, yield line analysis, risk and safety, wireless sensor networks and NDT applied to bridges, computer vision applications in civil engineering and the management of bridges.