A Guardian correction from August 12 demonstrates why you should be absolutely sure when you use Britain (for either the United Kingdom or the island) or England (for the country):
Another common error cropped up when we used Britain instead of England: What we have loved, others will love (page 34, also from 10 August). Hen harriers do breed in Scotland. No chicks hatched in England this year.
This is the second time in recent weeks that the Guardian has given readers a geography lesson via a correction; recently, the paper corrected a correction about the spelling of a British village.