Shy,
What part of "Maintain VMC" did you not understand?
In my Country....One must have an ATC Clearance to operate IMC in Controlled Airspace.
We are also required to maintain a listening watch (and respond if called) to the assigned ATC Frequency issued in the IFR Clearance as well as making required Reports to ATC.
We do not do IMC in Controlled Airspace without both an ATC Clearance and the Ability to talk to ATC itself.
There is very little Uncontrolled Airspace in this Country during IFR Weather Conditions.
I refer you to our FAA FAR Part 91 and Airman's Information Manual (AIM).
You can even take a gander at our Terminal Enroute Procedures (TERPS) if you are interested.
Please do not confuse the way you do things in the UK to anywhere else in the World. The UK is but a very small place and far too often has a unique way of doing things.