The most logical explanation is that the event was ordered by the " Deep State", and the hit was done by a German EU asset working in Porton Down. Had the Russians done it, then it would have been a professional hit, not the amateur botch up that one expects from EU "assets". There is no conceivable reason for the Russians to have done it, by the way.
That is the only explanation that fits all of the "facts" that have come to light.
Could you explain in a little more detail? Why wouldn't the Russians have any motivation? Didn't Skripal betray Russia? What would make Germans want to kill him? The article I shared implies that they've identified several Russians that were involved in the assassination attempt. You don't believe that? What makes you think that Russian assassins are better than Germans?