 The royal prerogative is in much use in the realm of foreign affairs . It is the monarch who recognises foreign states ( although several statutes regulate the <unk> enjoyed by their heads and diplomatic representatives ) , issues declarations of war and peace , and forms international treaties . The monarch also has the power to annex territory , as was done in 1955 with the island of <unk> . Once territory has been annexed , the monarch has complete discretion as to the extent to which the government will take over the former government 's <unk> ; this was confirmed in West Rand Central Gold <unk> Company v The King . The monarch also has the power to alter British territorial waters and cede territory . Her freedom to do these things in practice is doubtful , in that they might deprive British citizens of their nationality and rights . When the island of <unk> was ceded to Germany in 1890 , Parliamentary approval was first sought . The monarch can also regulate colonies and dependent territories by exercising the prerogative through Orders in Council . The courts have long fought against the monarch 's use of this power : in R ( <unk> ) v Secretary of State for Foreign and Commonwealth Affairs ( No 2 ) , the Court of Appeal ruled that using Orders @-@ in @-@ Council to <unk> judicial <unk> was an unlawful abuse of power , although this ruling was later overturned . 
