To obtain a Road Fund Licence tax disc which by law has to be displayed on the windscreen you have to have a valid MoT certificate, valid Insurance certificate and pay at least 6 months tax, a year and you get a discount.
But using a system know as CUE (well that is what we send our data to) it is correct to say that a car without insurance can be clocked by the bogeys (Old London slang = Police) and a ticket issued - or even it can be taken to the crusher. You have two weeks to respond, you can get stopped by mobile Police too and picked up by fixed cameras additionally. You have to tell the DVLA if your car is "off the road" too.