Why so cheap...?

For some reason a lot of the stuff at the supermarket is cheaper here. Obviously even when you convert it into AUD. It's really odd! Best find was a pack of 16 ibuprofen tablets for 20 pence. That's less than 40 cents! WTF?!!! Makes me feel like we were being totally ripped off in Australia :P

At least it makes the expensive London rent and public transport easier to cope with :)