Comment 2 for bug 91368

Purging the contents on /var/lib/apt/lists and /var/lib/apt/lists/partial seems to have unstuck things (making sure that the partial directory remains and the lock file is untouched).

I suspect that all I may have needed to do was trash the file in /var/lib/apt/lists/partial, but it is too late for me to confirm that.

I guess apt should grow some smarts about purging broken files from this area, as it doesn't seem possible to do so without resorting to arcane commands in a root shell.