Broadband Speed: Apartment Confusion

Hi i wondered if anyone could help me resolve an issue with my broadband speed.

I live in apartment of 6 flats. I am on Sky broadband via a BT line. The master (NT5) sockets are all on the ground floor in the wiring cupboard. From there a standard BT internal wire runs to a secondary box in my apartment.

From the socket in my apartment I get between 64-160kbps.
From the master socket i get between 1-1.4mbps.

Obviously this is a wiring issue, so I ran another run of wire down the stair-well to check this theory. No speed increase. I an an extension lead (a cheap argos one), and the speed went up to 900kbps. I have also re-punch-downed all the wires and replaced the sockets at both ends. No improvement. The best speed is still from the master.

I am not sure what else to try. The wiring in the master socket (blue and blue/white) go into slots 5 and 2 to the secondary socket. Incidently, when I wire in the green pair as well from the master to the secondary (in the same slots), the speed in my apartment goes up to 700-800kbps.

All very confusing, but has to be the wiring. Everyone in the block is having the same issues. Is there anything else I can do to improve the speed? Perhaps a different wiring order or something?

Thank youu

A long extension lead can/will act as an aerial and pick up �noise� from electrical sources close by e.g. 240v ring mains; central heating pumps; the potential list is endless.
�Noise� will adversely affect the ADSL signal
This is more likely to happen if your extension is running in a common conduit with other wires
A poor quality extension lead will also have a similar effect

Try a �twisted pair� cable such as CAT5E; the �twists� tend to cancel out �noise�.

http://en.wikipedia.org/wiki/Category_5_cable show the type you need.

It comes in bulk reels of 305 metres which may be more than you want (and too expensive)
A lot of companies such as cableuniverse.co.uk ( I just give this as an example -NOT a recommendation) sell varying lengths of cable with Ethernet connectors on either end. You can just chop the connectors off and use any pair you choose. It may be cheaper than buying bulk�

Even with a better quality extension �noise� may still be a problem.
Try to run the cable away from any obvious source of electrical �noise�.

It does not matter which �pair� in the CAT5E cable you use as long as you connect the same two colours to the 2 & 5 connectors in the master and extension,

is terminal 3 connected ?

No, I removed terminal 3 (orange) wire.

There was a slight improvement but nothing amazing.

What's it like if you just use the green pair (remove the blue one)? If that works then it would suggest that there's a fault in the blue pair in the cable. If the same spool of cable was used for all the extensions in the block and there's a manufacturing defect this might explain everyone having the same problem...

If green works but blue doesn't you might have a simple solution on your hands.