Shares penalties

Have been asked to send in bank statements by UC and have undeclared shares on one of them.
On my initial claim I had genuinely forgotten I had them as they only pay out pence ie: £ 1.50 etc and they are in a fairly redundant account I never use or look at.
The problem is later on in further claim reviews having realised that I forgot to mention them I became frightened of how it would look and the repercussions on so just kept not mentioning them as they are low value anyway.
At no point have they ever paid any dividends with any value that has taken me over £6,000 nor are they worth much if sold, which is why I just never bothered to look at them. Again, the worth of the shares would not take me over £6,000 threshold.
If I declare them now or just let UC discover them on statements what are the likely penalties and repercussions? Has anyone else ever been in this situation?
I am on UC with a LWCRA element

Thanks for reply David,
However although I am under the threshold it is the fact that I have not declared these low value shares over the past years that is worrying me. If I declare them now then they will say 'why didn't you declare them some years ago' and will assume I have acted fraudulently by not declaring them ( even if negligible anounts) as they they are not going to understand how it is that once you make an error by forgetting to declare something it then becomes difficult to then declare it due to fear of facing recriminations or fines for non declaration. They will then probably ask for documentation going way back that I cannot provide.
I do not understand shares or how they work so have never really looked at them or been interested, let alone know how to access any past paperwork on them. Most of the post I have onthese is over my head so we're probably binned.

Thankyou David for your response. You have helped me see that I am probably over stressing. I will download my statements for them as such small amounts may not draw attention as long as I am clearly under the £6,000 threshold to be able to receive benefits.