During your test, was the rear fog light switched on?
Starter986 makes a good point. Our cars' rear fog light only illuminates on the left (road) side of the car. It's possible there's a fog light bulb missing on the right because it never came with one when it was delivered to the US. In countries where the road- or driver's-side of the car is on the right, the fog light bulb is on the right (and presumably no bulb is installed on the left).
If you had the fog light switched off during your test then it could be a faulty brake (or stop light) switch. I'd do a search for that and see if anyone else had similar symptoms.
This first pic is with my ignition on and headlights on. The second pic is with all lights on, inlcuding fogs. Theres no one in the car so the brakes are not lit up, and high beams are off if that matters.
