How can I remove old Ubuntu backups?

I am running Unity on Ubuntu 12.04 and have started using the backup program. I can't find anywhere to manually remove old backups. I don't want to wait until the disk drive gets full, as it is also used for other things.

From https://help.ubuntu.com/community/DuplicityBackupHowto:

Deleting old backups

You can invoke duplicity followed by remove-older-than and a time constraint. The example script removes backups older than one year:

duplicity remove-older-than 1Y --force ftp://[email protected]/etc

It is not possible to do a backup (full or incremental) and delete old files with the same command.

The Ubuntu Backup tool ist based on "Déjà Dup Backup Tool", which has duplicity as a backend.

when you go to system settings and click on the back up icon you should be presented with several options .By default ubuntu 12.04 will try to put your backups on ubuntu-one. You can also choose another location to store the backups locally. to do that, choose storage button and pick location from the drop down menu. You can also change the option of "Keep backups forever" to a month . This will automatically remove older back ups for you.You will find that option in the schedule section.