How can I permanently disable my headphone jack and use my laptop's internal speakers?

My laptop’s headphone jack is broken and now permanently thinks that headphones are plugged in when they aren’t, thus always muting the internal speakers.

Through the Audio Volume applet I can select the speakers instead and that works, however it is not permanent. Sometimes when other audio devices are connected or disconnected (e. g. Bluetooth headphones or HDMI), or when I reboot my laptop, it defaults back to the non-existing headphones.

Is there a way of permanently disabling the headphone jack and always using the speakers?