How to disable screen lock in Ubuntu 14.04 / Unity?

There is two steps involved into completely disabling the lock screen in Unity.

1. Go to Brightness & Lock panel from the Unity Launcher. And set Turn screen off when inactive: to Never
2. Install "Unity Tweak Tool" with sudo apt-get install unity-tweak-tool. Run it from the Launcher and select System > Security > Enhance system security by disabling Desktop lock