At 1.25 PM, RAF Hudson reconnaissance plane of 220 Squadron reports a German cruiser and 6 destroyers (part of Marine Gruppe 1) heading North. 12 Blenheims and 24 Wellingtons bombers are called in and bomb the ships unsuccessfully. http://en.wikipedia.org/wiki/Lockheed_Hudson
The British response is a disaster. The Admiralty assumes German surface raiders are breaking out into the Atlantic (ignoring the possibility of coastal landings in Norway) and prepares to engage the German fleet in the open sea. Royal Navy’s Home Fleet (battleships Rodney & Valiant, battlecruiser Repulse, 2 cruisers & 10 destroyers) delays leaving Scapa Flow until 9.15 PM and misses the chance to intercept the troop-laden German warships. In addition, 1st Cruiser Squadron at Rosyth disembarks troops to engage in the ‘sea battle’, losing the opportunity for rapid landings in response to the German invasion.
British submarines HMS Shark & HMS Seawolf leave Harwich naval base to patrol off Dutch coast and HMS Clyde & HMS Thistle depart Scapa Flow to patrol the coast of Norway. http://www.uboat.net/allies/warships/ship/3426.html