You need the equivalent of TRIAC phase-control dimmer, which has a AC zero-crossing detector, followed by a variable delay from the zero-crossing to when the Triac gate is pulsed. In your case, the phase delay should be controlled by an integrator which slowly ramps up over the delay period.
Rather than doing this with analog electronics, a much better way would be to use a PIC driving a Triac.
You could start with a circuit similar to this one. Note the use of R in the opto coupled version. The circuit would need modified for 220 VAC from 120 VAC but you see how the dimming is done using the opto coupler. Then just make up a sawtooth generator to provide the voltage and amplitude for the dimming. Possiblly working from something like that. Maybe someone here has a turn key ready drawing.
<EDIT> Mike is posted a good idea while I was stumbling around here. </EDIT>
Wow, they certainly do.... kit K8028. Does exactly what I wanted and saves £68....
Could probably save a bit more not using a kit but this is fine for my level of acomplishment in electronics I am not beginner but not really novice either.