I am being lazy with the cites but the circumstances are pretty well understood now:
The C-in-C was on much higher ground with a panoramic view of the whole battlefield. Some British guns had been captured in some redoubts on one of the hills. The order was intended to get the Light Brigade to stop the Russian removing the guns as they were shaping up to do.
The written order however was a mess only referring to “the guns” and also being vague about other aspects of the geography of the battlefield. Basically no thought was given to the fact that those receiving the order would not be able to see what the C-in-C could see and so could easily misinterpret the order.
The Brigade Commander was confused, “Which guns?”, and sought clarification from the dispatch rider. But instead of clarification all he got was the reaction of an outflung arm in the general direction of the enemy and something along the lines of the phrase “There, sire, are your enemy. There are your guns!”
Unfortunately the direction of the outflung arm, whilst towards the hills on which the Russians were preparing to remove the captured guns could also be interpreted as being down the valley lined with Russian guns and with guns and cavalry at the far end.
The order required immediate execution and the Brigade Commander, having sought and failed to get clarification, obeyed. I cannot see what else he could have done in the circumstances - for all he knew some awful situation may require what seemed to him to involve the sacrifice of his Brigade.
As a postscript, the dispatch rider Nolan, who was part of the Brigade and stayed for the charge rode, early on charged ahead of the Commander leading out the charge, which was still at a trot, shouting and waving his arms but was immediately killed by a Russian cannonball or possibly shell. He was dismissed as a hothead. Some now think he had finally realised that the Brigadier has misunderstood him, and his orders, and was leading the Brigade not to prevent the removal of the British guns but into the “Valley of Death”. The rest as they say is history.
Actually 1/3 losses were pretty light for what they actually achieved. They did reach the Russian guns at the head of the valley and killed the gunners thus disabling them, but then were cut to pieces by Russian counter-charging cavalry. Their “light” losses were partly due to the Heavy Brigade taking action to cover their retreat but also as the Russian flanking guns did not engage them on the return trip. Whether that was due to pity or another military cock-up is open to debate.
What the British (and many other) armies lacked at that time was not so much good generals but proper military staff to organise things (medical, shelter, rations etc) properly, including the transmittal of orders. Historically that had happened under good commanders (e.g. Wellington) who took pains with everything but not under most others. A proper Staff would of course that the element of chance away to some degree.
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