I've been trying to think of a good British English term for a summer job, the equivalent of American English Internship.
I'm sure that when I've worked with students my company had hired over the summer holidays, we used to the the term studentship, but researching a little further this seems to more correctly apply to a PhD scholarship in British English parlance.
I'm not specifically looking for a term which has connotations of either paid or unpaid work, but if the term has one of those connotations it would be useful for it to be mentioned.
Incidentally, it was my understanding that in American English, internship implied unpaid, but could nevertheless be qualified with either paid or unpaid. As @Martha points out however, it seems that limited duration is a more appropriate qualifier for the word.