Families across the UK will be busy planning this year's festivities after the government gave limited social mixing over Christmas the green light.Households will be allowed to form a 'Christmas bubble' made up of up to three different households so they can celebrate together.The bubbles will be permitted for a period of five days - from December 23 to December 27.Households that form a bubble will be allowed to mix in private homes, places of worship and public outdoor spaces.But what are the