In late March, the code-breakers at the Far East Combined Bureau, a branch of Bletchley Park, informed Somerville that the Japanese were planning a raid into the Indian Ocean to attack Colombo and Trincomalee and destroy his fleet. He therefore divided his fleet into two groups: Force A, which consisted of the two fleet carriers, "Warspite" and four cruisers, and Force B, centred on "Revenge" and her sisters and "Hermes". He intended to ambush Nagumo's fleet in a night action, the only method by which he thought he could achieve a victory. After three days of searching for the Japanese fleet without success, Somerville returned to Addu Atoll to refuel. While refuelling his ships, Somerville received a report that the Japanese fleet was approaching Colombo, which they attacked the following day, on 5 April, followed by attacks on Trincomalee on 9 April. Following the first raid on 5 April, Somerville withdrew "Revenge" and her three sisters to Mombasa, where they could secure the shipping routes in the Middle East and the Persian Gulf. The four "Revenge"s departed from Addu Atoll early on the morning of 9 April, bound for Mombasa; they remained based there into 1943. Thereafter, the "Revenge"-class ships conducted convoy escort from Kilindini. The ship underwent a further refit in Durban from August to November 1942. In February 1943, "Revenge" and "Resolution" escorted the Operation Pamphlet convoy that carried the 9th Australian Division from Egypt back to Australia.