Hi all.
New to the forum and I have absolutely no knowledge of electrics...

At the end of my garden I have a workshop and garage. I'm currently 'doing up the garage'.
The garage has it's own consumer unit which does the garage and the workshop. There were lots of wires trailing off behind the old walls but weren't connected to anything. I spoke to a few tradesmen at work and they suggested I turn off all the power and simply disconnect the wires that led to nothing. I got as far as disconnecting the one that was attached to the round junction box, but when I turned the power back on something blew and I had no power.
When I flipped the breaker switches back on, I had power in the workshop but not the garage. Then, when I turned on a plug in the workshop everything blew again.
Next morning I've come to have a look at it all.....everything works in the workshop except the plug that blew.
How did removing that wire effect everything?? Wondering if it's a simple fix before I call someone to have a look....
Sorry if I'm not being too clear, total noob at electrical stuff.
I've attached some pics.
Thanks in advance.