On 25 November 1941 one of the heaviest losses of life, and the only loss of a Royal Navy battleship to a submarine at sea, occurred off Bardia, when HMS Barham was torpedoed at extremely short range by U-331, and sank within four minutes. 862 men went down with her, and her end was filmed by a war correspondent on board one of the escorting destroyers. The footage is at the end of this post.
HMS Barham underway off Devonport in WW2. IWM FL1472
HMS Barham was at the time engaged in an operation to engage potential enemy convoys, together with the other two battleships of the Mediterranean Fleet, HMS Queen Elizabeth (flag) and HMS Valiant, escorted by nine destroyers. The battleships were providing distant cover to the light cruisers of Force B, engaged in searching for the German merchants Maritza and Procida (see also this link and this link). Once the news had come through around 1630 hours that Force K out of Malta had sunk these, the battleships turned for Alexandria.
Her complete service history can be found at this link. The BdU (Commander Submarines) noted in his war diary the rather jubilant:
U331 – 1 battleship torpedoed in the Mediterranean. A new beautiful success.
Kapitaenleutnant Freiherr von Tiesenhausen, who did a radio broadcast on this attack in December 1941. Wikipedia.
The translated detailed report of the attack by U-331 can be found at this link.
A very detailed account by a surviving officer of her loss is at this link.
The interrogation report following the sinking of U-331 in late 1942 give further detail of the sinking of HMS Barham at this link.
The loss of HMS Barham contributed to the very high number of losses at sea suffered by the Royal Navy in the period of Operation CRUSADER, about which I have written at this link.
The video of HMS Barham’s loss can seen here, in the context of the overall newsreel. The list of men lost is at this link.
 Force B consisted of two cruiser squadrons, 7 and 15, with the cruisers HMS Ajax, HMS Euryalus, HMS Galatea, HMS Naiad, and HMS Neptune, with escorting destroyers.