sentence: non-metric units , allowed by united kingdom law for economic , public health , public safety or administrative use from 1 january 2000 , are limited to : the mile , yard , foot and inch for road traffic signs , distance and speed measurement , the imperial pint for the dispensing of draught beer and cider , and for the sale of milk in returnable containers , the acre for land registration , the troy ounce for transaction in precious metals .