Tinstaafl
It's legal for a PPL to fly IFR without at least an IMC or IR? That seems a bit strange.
Yup.
In the UK, on a CAA/JAA PPL, you can file/fly IFR in VMC in Classes F & G.
I suspect this is mainly to get around the situation welkyboy describes - where there is no night VFR in the UK.
You can be a PPL with night rating/qualification (but no instrument rating/IMC) and be legal at night.