Ring opening metathesis polymerisation (ROMP) is a relatively recent addition to the armoury of synthetic methods available to polymer chemists. Until recently it has found only a fairly limited exploitation in the manufacture of speciality elastomers. This review briefly describes the development of ROMP and indicates some of its industrial applications. The main emphasis, however, will be on work carried out in the Durham Laboratories during the last ten years in applying ROMP to the synthesis of new polymeric materials.