Nicola Sturgeon and Boris Johnson means lockdown restrictions will be temporarily eased for a five day period from December 23 - meaning people from up to three households can form "a bubble" allowing them to meet indoors. But Christmas mixing was branded a "terrible idea" yesterday by an Edinburgh-based academic who has advised the First Minister during the pandemic.Devi Sridhar, a professor of global public health at the University of Edinburgh, said: "Christmas mixing in the U.K.