Tallsar
Much of these records were destroyed in the move to AbbeyWood (1996). It was announced in 1995 ABW would be a paper-free environment, and there would be space for less than 10% of the necessary filing cabinets. Therefore, archive or ditch. The MoD archives (at Kew I think) couldn't cope.
I recall on our first day at ABW the security jobsworth asked to see our Classified Documents Register. He then asked to inspect the documents (often large books and manuals) in their secure place. He was pointed to a huge pile that had been dumped on the floor in the middle of the floorplate. And that was just the TS and S stuff!!