For some, Christmas only starts with the first reference to Winterval in the press.
But for me, I know that Christmas is around the corner when Cadbury's Creme Eggs appear in the shops. Last year, I saw them on Boxing Day. This year, the 17 December.
EDIT: A comment suggests that they are on sale year round elsewhere. I've not seen them on general sale outside the 'Easter' period (which starts earlier each year) and a source at Cadbury's has confirmed that they have been released earlier this year - although those of us with a bad habit have still had the rather good chocolate bar version available.
Oh - and I will make the point whenever somebody mentions 'Winterval' (usually the Daily Mailevolent). It was never intended to replace Christmas, but to form a 'wrapper' for all the end of year festivals celebrated by the diverse communities in Birmingham - Halloween, Diwali, Hanukkah, Christmas, Ramadan and Eid and even going as far as the Chinese New Year.