Technically speaking, the Royal Sovereign was not a true 'lend-lease' ship. Instead, she was a substitute for the Soviet share of the Italian fleet which had been handed over to the Allies. Following the Italian surrender, the Soviets were entitled to a part of the Italian Navy as reparations. In particular, they wanted large, modern ships to help cover convoys heading to Murmansk and Arkhangelsk. However, the Western Allies were uncomfortable with this. The Allies needed Italian cooperation to free up ships for operations in the Mediterranean and the English Channel. Taking ships off the Italians and handing them over to the Soviets would jeopardise this. As such, the Royal Sovereign, the American cruiser Milwaukee, eight 'Town' class destroyers (ex-American 'flush decker's, transferred to the RN under the Destroyers-for-Bases agreement) and four submarines would be loaned to the Soviets until the Italian ships were available. However, these ships would not be freed up for transfer to the Soviet Union until 1949. The battleship Giulio Cesare, cruiser Duca d'Aosta, five destroyers and three submarines were transferred over, starting in February 1949. Milwaukee and the British ships would make the return journey at about the same time.

To some extent, though, the delay in transferring the Italian ships was because the Soviets were clearly trying to hang on to the loaned ships. The Royal Navy received frequent suggestions from the Soviets that they would want to keep the loaned ships permanently, along with any ships sent over as reparations. This fact was debated in the House of Commons in January 1948, with both Labour and the Conservatives agreeing that the Soviets should not be allowed to keep the ships. Letting the Soviets keep Royal Sovereign would damage the prestige of the Royal Navy, and deprive the British economy of valuable scrap metal. As such, the British pushed hard for the return of the ships, against stiff Soviet opposition.

As far as what the Soviets learned from the ships, this was apparently limited. They had only been able to make limited use of Royal Sovereign and Milwaukee; both ships had served mainly to provide additional air defence at Murmansk. The destroyers had been more useful, supplementing the escorts for the convoys on the Arctic route. However, they were obsolete compared to much of the Soviet destroyer fleet. Similarly, Milwaukee, built in the early 1920s, was outclassed by the more modern Soviet cruisers of the Kirov class. Only Royal Sovereign represented something new to the Soviets, outclassing any battleship they had in service; yet she was clearly outdated, having been completed in 1916 and only slightly modernised in the intervening years. She helped to demonstrate what the Soviets had already learned from three years of war; that battleships were outdated, and aircraft carriers were much more effective.