When Margaret Thatcher was P.M. with which country Britain waged a war to regain control of Falkland Islands ?

As a British Overseas Territory, the Falkland Islands enjoy a large degree of internal self-governance with the United Kingdom guaranteeing good government and taking responsibility for their defence and foreign affairs. In 1982, following Argentina’s invasion of the islands, the two-monthlong undeclared Falklands War between both countries resulted in the surrender of all Argentine forces and the return of the islands to British administration.