Funny you should say that, I suggested this morning that this could be an inside job, but my suggestion was dismissed by the site's supervisor, who instead offered a frankly ludicrous theory that the last company who hired the same site office as us kept a key, hunted down the next site it was on (somehow) somewhere in the Central Scotland area and then unlocked it overnight just in case there might be something of value inside. A theory so utterly fucking stupid that I was literally speechless and could only offer "Well, it's not going to be that is it?" by way of a response.