Yeah.. the word fuck does feel fairly modern even if it might not be. Words like bleedin', bloody and shyte, could all easily replace it and fit in well with the already British accents.. Also, what's up with every race having British accents?
It definitely is not modern. There is a book which records of a flyting in the reign of James 5th (of Scotland). He died in 1542. (A flyting is a contest between poets where they use a particular verse form to insult each other. Scottish poets were master of this genre.) The word used is wanfuckit, and there is an online translation of the flyting. Look for the flyting of Dunbar and Kennedy.
And that's the end of the history lesson.
