One of the most common questions that I used to get asked when I was a BT engineer was 'Can I move my BT master socket' and the answer was always 'You're not supposed to'. The fact is that BT (Openreach) own the cable and junction boxes all the way up to and including the master socket.
Whilst technically a customer isn't supposed to move anything, I can't say that I've ever heard of BT taking anyone to court over the issue. If you feel that you have the necessary skill to do the job properly then I don't suppose that anyone is going to moan. If you get it wrong then you'll end up having to call BT Openreach to fix it and that won't be cheap.
Why you might want to move a telephone point
One of the more common reasons for wanting to move a telephone point is that it is no where near an electrical socket or that it's in a drafty hall. In the early days of telephone installations (who remembers Buzby?) many telephones were hard wired and were often placed by the front door.
These days many of us have broadband so it's often a lot more convenient to have the router and master socket close to the computer. If you really can't move the NTE5 then you could consider running an extension to somewhere else in the house.
This method works well for a telephone but may not be the best solution for a router. My own wireless router is situated in the lounge but my home office is up stairs. I looked at various ideas when I was trying to get a wifi signal upstairs but ended up using powerline adapters
The idea of the NTE5
The idea is that it has a removable lower plate. Behind the plate is another socket where a phone can be plugged in. The intention is that any telephone extensions are connected to this plate but, in the event of a fault, the plate can be removed to isolate the extensions from the incoming line.
If the phone works without the plate being connected then it's down to the customer to repair the fault. If the phone still doesn't work then it down to the telephone provider to fix the line fault.
Types of phone socket
The most common socket in use is the NTE5 but there are also the older types out there. There are generally only 2 wires that attach to the back of an NTE5 and all that you need is a small cross-head screw driver.
The older line jack units such as the LJ2/1a do not have screw terminals at all, they use Krone connectors which require a special tool to insert the wires into the block. They are known as insulation displacement connections and are probably not something to play with.
So now you know whether you can move your BT master telephone socket or NTE5