This thesis reports the results of a novel investigation of the management of product design in the UK mechanical engineering industry. The research examined the management of product design, specifically the relationship between design and production functions, in the mechanical engineering industry as a whole. It measured the design performance of firms as measured by the amount of design modifications carried out after drawing transfer to production and the number of standard components in a design. A novel and unique two-pronged research methodology was developed. This consisted of a national survey of the UK mechanical engineering industry and a set structured interviews. The survey was a random, and thus representative, postal questionnaire survey of 860 companies. A response rate of 13 % was obtained. Two sets of case studies were undertaken: on firm's use of CAD and on design management. The structured interviews, of pairs of closely matched firms, were linked to the survey by an analytical bridge - design performance, as measured by design modifications after drawing release to production. Theoretically the study identified three possible solution approaches to bridging the design - production gap: methodology, technology and organisation. It was concluded that methodology solutions (DFA, QFD, BS 5750) had little use and impact in industry. Second, management's approach to, and use of, methods for design freeze, generational design and standardisation was the key factor in producing better performance. Technology (CAD) as a solution to the design - production interface was limited, due to its low diffusion, use for 2D drawing and technological limitations. It was shown for the methodology and technology solutions that organisation was the key - the better performing companies not only used certain techniques and technologies but used them better. These companies had an integration culture and a pro-active management. The complacency of firms was jolted by catalysts - TQM, commercial flops and the recession. It is concluded that firms will only improve their design - production integration when forced to by a catalyst. Simultaneous engineering, another catalyst, addresses itself directly to product design, and is thus recommended as the way to improve the competitive position of Britain's mechanical engineering industry.