Problems with apt-get update - GPG erros

[Paul Thompson]

Hi,

I am getting this messages when I run apt-get update -

Ign http://nz.archive.ubuntu.com edgy/main Translation-en_NZ
Ign http://security.ubuntu.com edgy-security/main Translation-en_NZ
Ign http://nz.archive.ubuntu.com edgy-backports/main Translation-en_NZ
Ign http://security.ubuntu.com edgy-security/restricted Translation-en_NZ
Ign http://nz.archive.ubuntu.com edgy-backports/restricted Translation-en_NZ
Ign http://nz.archive.ubuntu.com edgy-backports/universe Translation-en_NZ
Ign http://security.ubuntu.com edgy-security/universe Translation-en_NZ
Ign http://nz.archive.ubuntu.com edgy-backports/multiverse Translation-en_NZ
Err http://security.ubuntu.com edgy-security Release

W: GPG error: http://security.ubuntu.com edgy-security Release: The
following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu
Archive Automatic Signing Key <ftpmaster at ubuntu.com>
W: You may want to run apt-get update to correct these problems

Running apt-get update does not fix the problem. I realise that I need
to update the GPG key but do not know how to do it.

Guidance on this matter would be most appreciated.

Regards,

Paul Thompson