Is it possible to revert an entire SVN repository

svnundo

I just did something dumb with my SVN repository, I accidentally imported a load of stuff into the root instead of into a subfolder. It will take me ages to clean up…. unless there is an easy way to do a global revert on the repo? The help file talks about reverting working copies but there is no working copy for a newly-imported item. Is there a way to undo an import?

Duplicate: Roll back or revert entire svn repository to an older
revision