1998 Discovery 1
I've read here before that the solution to a locked steering/ignition issues is to unplug something on the steering column...:

Which plug do I need to unplug exactly in order to resolve the issue without compromising computer/battery etc...?? is ti the big white one or the little one with the two purple wires??
If anyone could be as specific as possible I appreciate it.

 

Hey ..What exactly is the issue you are having with the steering lock...???

Don't disconnect anything yet....

 

Agreed with above. I have not heard of many D2s with column lock issues. The key turns and the car runs but the wheel is locked?

That car doesnt have an immobilizer system. Your ignition cylinder is probably just toast. Undo the top two screws that hold the ignition on (flat cold chisel lefty loosey), under the two tiny phillips head screws holding the black connector onto the back and then turn it with a flat blade screw driver. If it starts replace the ignition lock cylinder. If it does not firther inspection will be necessary.

 

sometimes the steering wheel locks to a point of no returnthe key also does not turn at all... I have to disconnect the battery in order to be able to turn the key and unlock the steering wheel again. The shifter seems tight so either the lock is worn or the electrical release is bad?... I read somewhere here in the forum that the little plug that locks the steering wheel is the main cause of this issue...true?..can I just bring the car to a locksmith or do I have to take the keylock out myself and replace?? I thought the simple unplug the plug would fix it. true? which plug???? Thanks

 

Try finger plug.
.......

 

Reading the electrical manual, the only electrical thing I can think of that would potentially be causing the key to not turn would be the key-in sensor. That sensor utilizes the purple and purple/white wires you can see in that picture on the large white plug block.
However, I don't see how unplugging those wires would do anything. When there's no key inserted there's no connection; your problem seems to be that the key is not closing the connection correctly. Disconnecting the wires is going to have the same effect as not putting a key in at all.
The key-in sensor wires go back to the BCU via passenger compartment fuse 20. You might want to check that fuse.

But gor an actual solution you should probably just replace the key barrel, as has already been suggested.