Depends purely on the official involved. Some are absolute sticklers and won't allow a test without it, others don't give a rats This post will be deleted if not edited to remove bad language and will test away.
Why do they ask for it? I had my NCT on Thursday and spent a day looking for my VRC but again they didn't even mention it. While I was waiting for the test a man asked if his neighbour needed it for his NCT and he was told NO.
They told me some years ago that they only need to note/see it for the first NCT and its not required after that but I still prefer to bring it along in case I get a stickler who sends me away to get it.
Usually keep these type of documents in small fireproof safe for ease of find and handyness sake.
I also keep all the car's documentation together in the same binder. That way I know where to start anytime I need any document regarding the car.
I found the system really useful when I traded my car in at the beginning of 2008. Everything was completed mere days (that includes registering for tax, insurance switch, property cert).