The Mediterranean fleet was especially busy during this period even after the success of Matapan. So vital was the task of halting the passage of munitions from Italy to Libya that Churchill had urged Cunningham to block the port of Tripoli by running a ship into the harbour entrance. He had proposed the use of HMS Barham, a dramatic use of one of the battleships in the Mediterranean. Eventually it was decided that the probability of air attack meant that getting the ship into position to block was to likely to be too difficult to be worth risking a capital ship. As an alternative a surprise bombardment was delivered:
The Commander-in-Chief, Mediterranean, in H.M.S. Warspite, with H.M. Ships Barham, Valiant, and Gloucester, accompanied by destroyers, bombarded the port and shipping at Tripoli for 42 minutes at dawn on the 21st April; the Naval bombardment was preceded by bombing and flare dropping by R.A.F. and naval aircraft.
Air spotting was rendered difficult by smoke and dust from the air attack, but three or four ships were set on fire or sunk in the naval basin and two or more others hit as well as a destroyer; the harbour facilities and shore establishments were also seriously damaged, some 530 tons of shells having been fired. No naval units were encountered and there was no reply from the shore batteries for 20 minutes.
There was no damage or casualties to our ships. During the approach naval aircraft shot down four troop-carrying aircraft and one bomber, and after the bombardment destroyed one bomber and defeated an attack by dive-bombers, one of which was shot down and one probably destroyed.
From the Naval Situation Report for the week.