Summer jobs in UK?

<p>Howdy, fellow parents! I suppose I could dig this stuff out by looking at some immigration laws, but I'm lazy... Does anyone happen to know - if an American citizen study in a UK university as an undergraduate student, is he/she eligible to work (e.g. as a paid intern) in UK during the summer? If paperwork is needed, which is most likely, is it complicated or hard to get? Thanks!</p>