Despite what you often see on the road, this is how it is supposed to be.
The construction and use regulations stipulate that a rear high intensity light should only be operative on the offside, so approaching/ following vehicles don't mistake them for brake lights, and that they don't mask brake light operation if they are fitted to both sides.
The construction and use regulations stipulate that a rear high intensity light should only be operative on the offside, so approaching/ following vehicles don't mistake them for brake lights, and that they don't mask brake light operation if they are fitted to both sides.