In the field of infrared optics (8-12 microns) there is an increasing requirement for continuous zoom telescopes operating with scanner systems. To date, zoom telescopes have for some applications been precluded due to excessive length. An exercise was undertaken to explore the possibility of length reduction. The study resulted in the design of a compact, high performance IR zoom telescope. This design and its development will be described including achromatisation, athermalisation and tolerancing aspects.