My ex and I are filling out forms for our DLA receiving 4 year old DS to get him a council pass. They want his National Insurance Number. I have always written DS's National Insurance number as the reference on his DLA form as I was under the impression that was his National Insurance Number. Ex says while the reference is set out like a national insurance number (Letter letter 6xnumbers letter) it can't be DS's National Insurance number because he isn't 16. I've left it blank but can anyone answer me, is that his National Insurance Number?