"The Darkest Rush Hour"

From Wiki and Wiki:

The film commences in May 1940, on the last day of British rule in Hong Kong in late 1997.

The opposition Labour Party in Parliament demands the resignation of Detective Inspector Lee of the Hong Kong Police Force for being too weak in the face of the mysterious crime lord Juntao.

Lee tells Conservative Party advisers that he wants Sang, Juntao's right-hand man as his successor and manages to escape. Sang does not want to become Prime Minister as he is busy recovering numerous Chinese cultural treasures stolen by Juntao.

So King George VI must choose the only other man whom other parties will support: Winston Churchill, whom he presents as a farewell gift to his departing superiors: Chinese Consul Solon Han and British Commander Thomas Griffin, the First Lord of the Admiralty.