If you re-draw the schematic it is simply a bridge rectifier across the 220V with a capacitor as current limiter. The electrolytic caps are across the DC output and the tube is fed via 47 Ohms and another diode. In other words it works on DC and has no start-up circuit. I would be worried the tube might explode and release mercury vapor. It would probably work equally well (or badly) with just the series capacitor and tube in series across the AC and all the other components omitted. With the values shown, at 50Hz and assuming no harmonics or spikes, the tube could be dissipating over 30W.
Brian.