It's 1955, and made up as pure vanity for a special event in Bedfordshire on 30th April that year. The company that makes them has a web site: http://poplargreg.com/ I originally had them made for my miniature traction engine. .
There is a thread in the Malvern Arms section of TM on this also.
Better phot showing the tax disc in-situ, with Emily doing her 'Maggie Thatcher in a tank' impersonation.
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