Definition of do something for one's country (or England etc.) in English:

do something for one's country (or England etc.)

phrase

British
informal
  • Used to indicate that someone does or can do the specified activity with great enthusiasm or tirelessness.

    ‘you eating for England, Barry?’
    • ‘There are some people - some of whom I actually know - who could bore for England on the subject of cello strings, but I am not one of them.’
    • ‘His natural exuberance - the man could talk for Scotland - played a large factor in his being where he is professionally.’
    • ‘I used to be greedy and could eat for England, but the great thing is I lost the weight by eating the same things but just more sensibly.’
    • ‘They might only be young, but toddlers can sulk for Britain.’