The money of poor people in rich countries going to rich people in poor countries

I believe that is how someone once described aid to third world countries so I was unsurprised to read that:

"Sudan has refused to hand back half a million pounds worth of British taxpayer-funded equipment seized from aid agencies six months ago.

British diplomats in Khartoum have demanded that the vehicles, computers, office equipment, medical stores and cash be returned so that it can be redistributed.

But Sudanese officials have scoffed at this, saying that neither the British government nor the aid agencies have "the right to control these assets"."

The west has thrown more and more money at largely unattractive African governments for 30+ years and I wonder what percentage of the money has made it to the poor of those unfortunate countries and what percentage to the bank accounts of their rulers?