In February 2020 the US administration of Donald Trump agreed the withdrawal of US troops with the Taliban by May 2021, without including the Afghan government in the deal. One would presume at that point there was some entity within the UK government that was responsible for managing the UK withdrawal based on this timescale. This would include evacuating UK citizens and those Afghans who were ensured protection in return for working with the UK forces, and ensuring sensitive documents at the embassy are not available to hostile entities.
It seems that there were problems with this operation, despite the timescale being extended significantly by Joe Biden. The Freedom of Information Act 2000 allows individuals to request information held by public authorities to allow voters to make informed decisions within the democratic process. Gov.uk lists 579 entities to whom one can make a FoI request. Which would be the appropriate entity to make a request for information about the planning and implementation of this withdrawal, in particular the early stages after the initial decision to withdraw?
I am particularly interested in the United Kingdom, but other countries that are in the same position would also be interesting.