Hi all, first post here.

I've recently moved into a new flat, and the landlord had set up some internal wiring, and had a BT engineer round to relocate the master socket to a more suitable location.

Now, the wiring is a bit strange, and I'm not sure how the ownership works, so I'll post some pictures and you can see what I mean. Apologies for the blurry pics, they're from a mobile phone.

Drop wire and junction box:
http://img143.imageshack.us/img143/9038/image226nw0.jpg

The black wire on the left is the incoming drop wire. The yellowy wire is the line going down to the master socket.
The white-painted cable is a CAT5 cable that goes through to an as-yet unwired socket up by a shelf - intended for a router.

Master Socket (Openreach branded faceplate):
http://img93.imageshack.us/img93/7082/image228zz1.jpg

The central cable is the incoming phone line from the junction box.
You can see the Green/White pairs going up to the main connectors (the brown pair is unconnected).
You can also see the Orange/Blue & White pairs connecting to the faceplate.

You can also see the outgoing Orange/Blue & White pairs coming from the faceplate that go through to an extension.

OK, that's the setup explained. I have two questions that are baffling me:

1) Why are the Orange/Blue & White wires from the incoming line wired to the faceplate. I thought these should be unused and the faceplate will pick up the signal from the correctly wired Green & White pair once the faceplate is placed on?

2) How does the ownership of the CAT5 cable work? Since this is coming out of the BT-branded Junction-box separately to the other cable which connects to the master socket (where the other extension is correctly wired).

bump?

okay, basically going off the pic's and your description, the line has been incorrectly wired.
i'm right in think that the cable from the junction box has the greens connected to the screws on the nte5, and the oranges and blues on the faceplate? if so, you will have the adsl signal going inopposite directions in the cable and can cause problems. the correct wiring method should be, a cable from the junction box(our responsibility) to the nte5(also ours) then another cable back to the ext'n for the router.
as it stands you have no true de-marcation point as our cable to feed the nte5 is also carrying an ext'n. it's called back feeding and is very common amongst the laziest of engineers. annoys the hell out of me though cos i have to re-cable every house up to spec wen on a b/band fault. anyways slightly off topic.
with regards to the whole ownership malarky, we will cover the cable into the junction box, the junction box, and the cable to the nte5 and nte5. the rest is your's/landlord responsibility.
there is no rules saying that you can't use our internal junction boxes to join cables together in, however if you alter our connections in them then you do leave yourself wide open to possible charges incase of faults.
any chance of a piccie inside the junction box?