I think its worth mentioning a little recognised feature of privileges of the UK PPL in UK airspace. I do not know what applies elsewhere.
An earlier post refers to the limit of 3k vis and sight of surface, and several have noted that within this limit, a 'vanilla' PPL can choose to fly VFR or IFR as he(she) wishes in Class D or below.
The absence of the vertical and lateral limits on distance from cloud makes little difference at or below 3000ft, but above that, the difference is very great. eg, if the cloud base is 4000', you may not fly VFR above 3000', even if the vis is 50k. The PPL without IR/IMCR is fully entitled to fly IFR in IMC in this space, provided the other IFR rules are met. We get a lot of days with 2-4 octas tops 4000-5000'. This allows the plain PPL to fly 'on top' in these conditions, provided he keeps the 3k forward vis, because of the gaps which allow him also to see the surface. It is impossible to get there VFR because of the inevitability of infringing the lateral and/or vertical limits when climbing/descending through the layer.
In my view it is both safer and much more relaxing to fly any reasonable distance at an appropriate quadrantal FL in visual conditions, than cope with all the various other flying activities and airspace restrictions below.
The NPPL specifies VFR only, as do the current limitations on permit a/c.
I think it an absurdity that under the very large area of the London TMA with a base of 3500', a cloud base of 4000' prevents VFR flight from using the invaluable extra 500' above 3000'. All areas under the TMA are very highly used, and every bit of space is needed. Quadrantal rules do not apply below the transition altitude, which there is 6000'.
Perhaps Bookworm would like to make further comment?
MikeJ