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The Imperial units is a collection of English units, first defined in the Weights and Measures

Act of 1824. The last Imperial Standard Yard in bronze was made in 1845.

This system was refined and reduced until 1959.

These units are used in Commonwealth countries and also in the United States. Whilst

these two systems are quite similar there are a number of notable differences between

the Imperial and U.S. systems. 

In 1959, the United Kingdom began legal transition to SI units.

In 1995, the United Kingdom completed its legal transition,

BUT a few such units are still in official use:

• lengths in inches on the chidren's rules,
• most roadsign distances are still in yards and miles,
• speed limits are in miles per hour,
• the troy ounce still may be used for the weight of precious stones and metals,
• draught beer and milk must still be sold in pints,
• Fahrenheit equivalents are often given after the Celsius in weather forecasts.

Many people still measure their weight in stone and pounds, and height in feet and inches,

but these must be converted to metric if recorded officially.