Reports on the research and development work carried out at Central Research Laboratories Ltd [CRL], concentrating on their physical and chemical sensing techniques and the manufacture of sensors based on silicon field effect transistors [FETs]. Describes the use of FETs in ion sensitive field effect transistors and gives their advantages over conventional ion selective electrodes, suggesting possible application areas might be in clinical blood analysis, soil sampling and water testing. Also looks at the use of FETs in gas sensitive field effect transistors, which have been used in chicken house atmosphere monitoring and for detecting hydrogen induced cracking in oil and gas pipelines. CRL has also been involved in the development of low cost electro‐chemical gas cells by new manufacturing techniques. Concludes with the range of sensor technologies that CRL has expertise in.