Britain has long been a Christian country, therefore, the Church ordained that no secular 'holiday' would have presidence over the Lords' Day. Christmas can be a Sunday, because that is a religious holiday (Holy Day), but Boxing Day can never be a Sunday because it was a secular day. Saints days never change (except by intervention from the Pope) so St Stephens' day is always 26th Dec, as the first Christian martyr. Boxing day seems to have been the day for secular activities - hunting, mumping, dancing and visiting families. It was also the day that many agreements of employment or tenancy came to an end. 25th Dec, the actual quarter day being a day of obligation, the moving was usually done on the following day, 26th. (The other quarter days were Lady day 25th March, midsummer 21st/22nd June and Michaelmas 29th Sept).

The rule of thumb to remember in the UK is that religious holidays can never move date(yeah, OK, Easter does, but it's based on the lunar calendar rather than the Gregorian one) but secular holidays (an oxymoron) can.

I remember having a Christmas Sunday in the not too distant past, and I remember having the same discussion with someone....

LTS