The USDA Climate Zone system is used internationally, and Shropshire is Zone 8 (10º to 20ºF /-12º to -6º C). Of course it is important to remember that the USDA Zones only measure one factor, minimum annual temperature. Other factors such as high temperature and average wind and humidity levels are not considered. The USDA Zones can be used globally as long as one remembers they are only useful in determining cold hardiness.
Of course, there are other classifications: The Royal Horticultural Society does have an equivalent system ranging from H1 to H7. Australia and Canada do have other systems. Canada's is complexly multi-factorial, as are the Sunset Magazine Climate Zones which were developed for western North America. The American Horticultural Society has developed a Heat Zone classification that calculates the number of days when temperatures exceed 86 °F/30 °C. None of these are widely used internationally, though that could be done.