The bible says saturday is the last day of the week, which means societies with a strong christian tradition use sunday as the start of the week.
Sunday is defined in law as the start of the week in some bits of English law, so there's that.
Sunday is defined in law as the start of the week in some bits of English law, so there's that.
Italy, Spain, Ireland, England... actually all european countries (AFAIK) use Monday as the start of the week. All countries with a strong christian tradition.
The only countries I know that use Sunday as the start of the week are the US and Israel.
A quick search in wikipedia[0] also mentions that it's used as the first day of the week in Hebrew tradition and in some muslim countries.
[0] https://en.wikipedia.org/wiki/Sunday#Position_in_the_week
At the moment there's some inconsistancy:
Sunday to Saturday: https://www.gov.uk/maternity-pay-leave/pay
Monday to Sunday: https://www.gov.uk/guidance/statutory-sick-pay-manually-calc...
Googling for ["sunday to saturday" inurl:gov.uk] or ["monday to sunday" inurl:gov.uk] shows a bunch of examplesof each.
EDIT: You asked for links, so here's something from 2009 asking why it's so hard to find a calendar that starts on a monday: http://www.theguardian.com/notesandqueries/query/0,,-200944,...
> Why is it so hard to find a calendar that starts the week on a Monday, not a Sunday? It can't just be my family who gets outraged by this.
And here's something else from 2009 which (weirdly) explaining why it's so hard to find calendars that start on Sunday, not Monday.
http://www.telegraph.co.uk/comment/letters/6495398/Officiall...
tl;dr England used Sunday as the first day of the week until they started using ISO standards for time.