unknown blue lead on my battery?

[hillclimb_clio]

I have just noticed a heavy duty blue lead coming off my battery on my 172 Cup - it doesn't seem to attach to anything & terminates in a plastic block with some kind of connector inside so I'm wondering if it was used for some fancy ICE set up or similar by a previous owner? I'll try & get a pic up - I'm sure that'll help more than my crap description!

 

[-Leigh-]

Probably a power lead for an amp. If it goes nowhere, it's doing nothing, so take it off.

There are no blue leads from the battery as OEM.