Fair advertising of goods and services is a fundamental issue in consumer protection. Britain's failure to organise a smooth and rapid transition from imperial to metric has led to many advertisements that make confused or misleading use of measurement.

In the example below, it is difficult to compare the price of carrots sold "loose" per lb with the price of a pre-packed 1 kg bag of carrots without a calculator.


Despite the fact that the current Price Marking Order requires goods offered for sale to be priced in metric units at the point of sale, there is some confusion over whether and how far advertising is covered by the Order. As a result, Trading Standards Officers are reluctant to intervene, and some retailers have taken advantage of this situation to adopt an aggressive policy of advertising goods in whatever measures (imperial or metric) appear to show their goods to be better value for money. For example:

  • Carpets may be advertised per square yard rather than per square metre (m2) since the former is smaller and appears to be cheaper (even though the unit price may be the same)
  • Vegetables may be advertised per lb even though prices at the point of sale must be per kg. Again, this is done because 50p/lb may appear to be cheaper than £1.10/kg, although the unit price is the same.
  • For the same reason, cheese may be advertised per 100 g since this quantity is less than ¼ lb
  • "Special offers" such as "50p off a gallon of petrol" are advertised since this appears to be a more dramatic reduction than the equivalent "11p off a litre".

Where goods are advertised exclusively in imperial measures, it is impossible to check at the point of sale whether the actual (metric) price charged corresponds with the (imperial) price advertised without a calculator.

The effect, if not the intention, of these practices is to mislead the customer while remaining strictly within the law and thus gain a commercial advantage - especially over more scrupulous traders.

UKMA considers the solution for this unsatisfactory situation is to bring advertising explicitly within the scope of the Price Marking Order. It should be illegal to advertise goods for sale giving prices, weights, quantities or other measures exclusively in imperial units. Metric units should be mandatory, with the option of a supplementary indication.