Gillingham took the lead through Danny Kedwell's far-post header, but Chris Robertson equalised for the home side with a close-range header.
Vale mounted pressure after the interval and it was no surprise when half-time substitute Pope headed home in the 63rd minute.
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Jon Platt's conviction brings to an end a legal battle over unauthorised term-time absences that went all the way to the Supreme Court.
Simon's Blog - Bugs
Friday night's forecast for the west of the region