Ubuntu – Read only file system

I'm running Ubuntu 12.10, Upon opening any shell I get the following error:

/home/jack/.rbenv/libexec/rbenv-init: line 87: cannot create temp file for here-document: Read-only file system

I realised this wasn't simply a rbenv issue, as any file I try to write to returns an error saying the system is Read-only.

I don't know how else to describe my problem, each time I boot up the system goes through a disk check, where it supposedly fixes several errors in my disk.

Here is my /etc/fstab

# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda1 during installation
UUID=1cc4b2ab-a984-4516-ac25-6d64f5050244 /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=4e0dfeae-701a-43ce-b5c6-65f15ab3d8e3 none            swap    sw              0       0

The entire file system is read-only. I've tried the following

sudo fsck.ext4 -f /dev/sda1

which gave the following (shortened) output

/dev/sda1: ***** FILE SYSTEM WAS MODIFIED *****
/dev/sda1: ***** REBOOT LINUX *****
/dev/sda1: 1257080/45268992 files (1.0% non-contiguous), 50696803/181051904 blocks