Spare wire

Been tidying up a bit under the bonnet and found a spare wire that comes from the joint wear the gearbox joins onto the engine just above the hole to set TDC on the fly wheel. It looks to have brocken off , any body got a clue what it is and where it should go.
Cheers Stu  

What colour is the wire?

If brown - it's probably the rocker cover earth lead.

If not - it's for something else, and you may find out from the Haynes wiring diagrams which include wiring colour codes

can you get a pic of wire / engine up someone might spot where it's from