Citroen Xsara Hatchback Petrol 1.4 tapping noise (transmission?)?

Tapping noise when the car is in motion.

Frequency of noise increases with speed.

Doesn’t seem to be coming from engine as the tapping does not speed up when the engine is revved.

Depressing or engaging the clutch also does not seem to have any affect.

Could this be a transmission problem, gearbox, drive, axle etc.?