deb http://mirror.bytemark.co.uk/debian stable main non-free contrib
deb http://security.debian.org/ stable/updates main contrib non-free

devil:~# apt-get update
Hit http://security.debian.org stable/updates/main Packages
Hit http://security.debian.org stable/updates/main Release
Hit http://security.debian.org stable/updates/contrib Packages
Hit http://security.debian.org stable/updates/contrib Release
Hit http://security.debian.org stable/updates/non-free Packages
Hit http://security.debian.org stable/updates/non-free Release
Err http://mirror.bytemark.co.uk stable/main Packages
  404 Not Found
Ign http://mirror.bytemark.co.uk stable/main Release
Err http://mirror.bytemark.co.uk stable/non-free Packages
  404 Not Found
Ign http://mirror.bytemark.co.uk stable/non-free Release
Err http://mirror.bytemark.co.uk stable/contrib Packages
  404 Not Found
Ign http://mirror.bytemark.co.uk stable/contrib Release
Failed to fetch http://mirror.bytemark.co.uk/debian/dists/stable/main/binary-amd64/Packages.gz  404 Not Found
Failed to fetch http://mirror.bytemark.co.uk/debian/dists/stable/non-free/binary-amd64/Packages.gz  404 Not Found
Failed to fetch http://mirror.bytemark.co.uk/debian/dists/stable/contrib/binary-amd64/Packages.gz  404 Not Found
Reading Package Lists... Done
W: Couldn't stat source package list http://mirror.bytemark.co.uk stable/main Packages (/var/lib/apt/lists/mirror.bytemark.co.uk_debian_dists_stable_main_binary-amd64_Packages) - stat (2 No such file or directory)
W: Couldn't stat source package list http://mirror.bytemark.co.uk stable/non-free Packages (/var/lib/apt/lists/mirror.bytemark.co.uk_debian_dists_stable_non-free_binary-amd64_Packages) - stat (2 No such file or directory)
W: Couldn't stat source package list http://mirror.bytemark.co.uk stable/contrib Packages (/var/lib/apt/lists/mirror.bytemark.co.uk_debian_dists_stable_contrib_binary-amd64_Packages) - stat (2 No such file or directory)
W: You may want to run apt-get update to correct these problems
E: Some index files failed to download, they have been ignored, or old ones used instead.