The British Royal Navy learned of "Bismarck"s sortie after the Swedish cruiser spotted the vessels passing through the western Baltic Sea on 20 May; "Gotland"s report was passed to the British naval attache in Stockholm, who forwarded it to the Admiralty. British reconnaissance aircraft confirmed the Germans' presence in Norway. Now aware that major German warships were at sea with the intention to break into the Atlantic, the Royal Navy began to despatch vessels to patrol the likely routes, including the heavy cruisers and to cover the Denmark Strait between Greenland and Iceland. Another group, consisting of the battleship "Prince of Wales", the battlecruiser , and a screen of six destroyers, under the command of Vice-Admiral Lancelot Holland in "Hood", cruised to the south of Iceland to intercept the Germans once they were detected. "Norfolk" and "Suffolk" spotted "Bismarck" and "Prinz Eugen" on the evening of 23 May; "Suffolk" was fitted with radar that allowed them to shadow the Germans through the night whilst remaining outside of German gun range.