Main voltage controll

I would like to control the main voltage(240V,AC) so to get from close to zero to full main voltage.The circuit will be before full bridge rectifying and smoothing capacitors. In addition the circuit should be able to supply at least 10 amps. I know there are variacs but they are bulky and expensive. Any suggestions on how it could be achieved?
Many thanks,
Yves

Phase angle control is common but needs a considerably more complex control circuit to make it stable and reliable. The Variac method is by far the simplest and most robust way to do it.

What do you need 0 - 340 VDC at up to ten amps for anyway?