Vacuum tubes disconected?

Hi All,
While tinkering around under the bonnet of the disco I noticed something that caught my eye, A black tube with a T-piece on the end of it lying next to it 2 more black tubes that have broken off the T-piece. One tube goes to the rocker cover, one tube seems to go through the firewall and the other seems to dissapear somewhere near the front of the airbox. Considering the disco works fine I can't work out what these are for, any ideas?
It is a 1996 N reg discovery 1 ES 3.9L V8 Auto

Appears that is the tubes for your cruise control, so you disco is not working fine only part of it is.

Ah, not that we ver use cruise control, pretty hard to do 30mph plus down green lanes . Will re-connect and give it a try sometime!