[bitfolk] lenny volatile expired GPG key?

Hi all, I seem to have started getting this error in the last 24 hours: W: GPG error: http://apt-cacher.lon.bitfolk.com lenny/volatile Release: The following signatures were invalid: KEYEXPIRED 1269969909 KEYEXPIRED 1269969909 KEYEXPIRED 1269969909 W: You may want to run apt-get update to correct these problems apt-get update doesn't fix it, and the obvious google seemed only to suggest clock syncronisation problems (the clock appears to be correct). Any insight appreciated :) Thanks Joseph