Now retired from regular work, but will consider a challenging/interesting assignment.I am a principal systems engineer working in defence on complex air and land systems primarily in the UK. Additionally, I have experience in railway systems, networks and information management systems. Some kind recommendations in my LinkedIn profile describe my capabilities.I use both traditional systems engineering and modelling as necessary. I am practised with various technical disciplines such as system architectures, software engineering/ programming, safety and security engineering, ontologies and development-process engineering. I often collaborate with internal and external research organisations.Responsibilities have been as system architect, engineering manager and technical team leader.