406oc.co.uk

Hi all,
Quick question, doing a bit of pre MOT prep I found a rubber pipe about 1/2 inch inside diameter on top of the fuel tank by the fuel pump. Could'nt see or feel where it goes ?
Looks like the sort of rubber hose like heater hose, any idea anyone ?
Car is a 406 2.0 Hdi Estate.


Any help appreciated.
Thanks

The diagrams are showing me a couple of venting pipes but with the motto "except diesel fuel". Never saw anything like that when I had my tank out either