On the 5th April 1940 she sailed as part of the destroyer escort to the battle-cruiser HMS Renown and the cruiser HMS Birmingham in Operation Wilfred, an attempt to intercept the expected German invasion force, and if necessary, mine Norwegian waters. On the 6th April, whilst screening a mine laying operation, Glowworm lost a man overboard in heavy weather. Her CO, Lt Commander Gerard B Roope obtained permission to conduct a search for the missing man. After spending sometime looking for him, the Glowworm attempted to return to the group. On the 8th April, the Glowworm sighted a destroyer which, when challenged, identified itself as Swedish. It was in fact the German Von Röder class destroyer, Bernd Von Arnim, which very quickly opened fire, to which Glowworm responded. Unfortunately another German destroyer, the Paul Jakobi soon appeared. However, the Von Arnim was packed with invasion troops and soon both it and the Paul Jakobi turned and fled into a rainsquall. Lt Cdr Roope gave chase despite guessing that they were trying to lead him onto their main force, in an attempt to discover their whereabouts and inform the Admiralty.

     As the Glowworm emerged from the squall she came face-to-face with 14,000 ton the German Heavy Cruiser, Admiral Von Hipper armed with eight 8 inch and twelve 4 inch guns. The Glowworm laid smoke and conducted torpedo attacks from the cover of the smoke screen but failed to hit the Hipper. Glowworm had sustained substantial damage by this time and Lt Cdr Roope gave the order 'Stand by to ram'. The Hipper, realising what was happening tried to turn and ram the Glowworm but was too slow. The Glowworm tore into the starboard side of the Hipper amidships and tore 100 feet of armor plating away, damaged her starboard torpedo tubes and punctured two fresh water tanks. After ramming the Hipper, Glowworm drew clear, but received another close range salvo from the Hipper to which the single gun, commanded by Petty Officer Walter Scott responded. Glowworm by this time had sustained massive damaged and started to sink and Lt Cdr Roope gave the order to abandon ship.

    He went down to open the sea cocks himself and the ship started to sink, forcing men into the freezing water or onto her bow. The Captain of the Hipper, Helmuth Heye, gallantly stayed for over an hour picking up survivors. He positioned Hipper so that the tidal currents would carry the survivors to them.