Why should the British die for what the Zimbabweans won’t die for?
The popular “land reforms” (aka eliminate white farmers) instituted by Mugabe in 2000 was the catalyst for the current crisis. I seem to recall discussion of FR when it was happening that it would be disastrous and they would be seeking foreign aid. The consensus then was when the disaster came to let them stew. I see no reason to revise that opinion now. Hopefully the Brits are of the same mind.
Because the current mess in Zim was a joint project of the British and Jimmy Carter.
They made the mess, they should clean it up.