Initial blacklisted packages: 
Starting unattended upgrades script
Allowed origins are: ["['Ubuntu', 'lucid-security']", "['Ubuntu', 'lucid-updates']", "['Sanger', 'lucid']"]
Checking: dhcpcd (["<Origin component:'universe' archive:'lucid-updates' origin:'Ubuntu' label:'Ubuntu' site:'archive.ubuntu.com' isTrusted:True>", "<Origin component:'universe' archive:'lucid-security' origin:'Ubuntu' label:'Ubuntu' site:'archive.ubuntu.com' isTrusted:True>"])
pkgs that look like they should be upgraded: dhcpcd
<apt_pkg.AcquireItem object: Status: 2 Complete: 1 Local: 1 IsTrusted: 1 FileSize: 53464 DestFile:'/var/cache/apt/archives/dhcpcd_1%3a3.2.3-5ubuntu0.1_amd64.deb' DescURI: 'http://archive.ubuntu.com/ubuntu/pool/universe/d/dhcpcd/dhcpcd_3.2.3-5ubuntu0.1_amd64.deb' ID:0 ErrorText: ''>
check_conffile_prompt('/var/cache/apt/archives/dhcpcd_1%3a3.2.3-5ubuntu0.1_amd64.deb')
found pkg: dhcpcd
conffile line: /etc/dhcpcd.sh b5e7e78f7ae70a5d6e6619d58b477764
current md5: b5e7e78f7ae70a5d6e6619d58b477764
conffile line:  /etc/default/dhcpcd 5985e1dff4832ed1fef727da4809202f
current md5: 5985e1dff4832ed1fef727da4809202f
conffile line:  /etc/default/dhcpcd newconffile
current md5: 5985e1dff4832ed1fef727da4809202f
pkg_md5sum: 5985e1dff4832ed1fef727da4809202f
Package 'dhcpcd' has conffile prompt and needs to be upgraded manually
blacklist: ['dhcpcd']
Checking (blacklist): dhcpcd
pkg 'dhcpcd' blacklisted
package 'dhcpcd' not upgraded
InstCount=0 DelCount=0 BrokenCout=0
Packages that are upgraded: 
Writing dpkg log to '/var/log/unattended-upgrades/unattended-upgrades-dpkg_2012-02-20_10:22:55.343056.log'
All upgrades installed
Sending mail with '/var/log/unattended-upgrades/unattended-upgrades-dpkg_2012-02-20_10:22:55.343056.log' to 'unattended-upgrade@sanger.ac.uk'
mail returned: 0

Done downloading            
Package 'dhcpcd' has conffile prompt and needs to be upgraded manually

Done downloading