The current use of two sets of units in the UK continues to be a source of muddle and confusion. Young people are taught metric (SI) units in school but, in the outside world, still have to contend with units such as inches, feet, pounds, stones and miles. Specialist teachers and practitioners of the sciences are not blameless. This paper considers the fact that some units commonly used in physics, astronomy, and physics education are unnecessary, involve time-wasting conversions and frequently lead to confusion or even error. This unsatisfactory situation is illustrated by examples, and suggestions are made for a radical improvement.