MG S5 Reversing Behaviour

When placing my MG S5 in reverse, the default behaviour with no feet on any pedals is for the car to move backwards on its own (ie I have to have my foot on the brake to stop it).

Is this defailt behaviour? I was expecting it to sit still until I push the accelerator pedal.

I have had my MG S5 for a few months now and I'm really pleased with it, but having to brake to prevent the car moving backwards feels a little... unsafe.