'Brimstone' (ii) was an Allied unrealised plan for British forces to take the Italian island of Sardinia, by the time behind the Allied left flank in Italy in September or October 1943, with the French 'Firebrand' seizure of Corsica to follow about one month later (autumn 1943).

'Brimstone' (ii) and 'Firebrand' were just two of a raft of possible undertakings mooted at the time, others being the British 'Buttress' and 'Goblet' against Pizzo and Crotone, the US 'Musket' against Taranto, and the Allied 'Barracuda', 'Gangway' and 'Mustang' against Naples.

The plan was not pursued as the German forces on the island of Sardinia could exercise no significant impact on Allied operations in the Mediterranean theatre. The capture of the island had been envisaged first during the planning for the Italian campaign, an alternative to the campaign eventually undertaken (through Sicily and into southern Italy) being a 'left-hook' advance from Tunisia straight north into Sardinia before a double debouchment into northern Italy and, via Corsica, into southern France. The option was not adopted as the alternative offered safer maritime lines of communication and also provided the chance to draw German forces farther from the Normandy region scheduled for invasion in 'Overlord'.

As originally conceived, 'Brimstone' (ii) would have been executed by a British corps under the command of Lieutenant General F. E. Morgan and including Major General G. G. Simonds’s Canadian 1^st Division, but its final form 'Brimstone' (ii) would have used more substantial Allied forces, in the shape of Major General Ernest W. Dawley’s US VI Corps (Major General Ernest N. Harmon’s 1^st Armored Division, Major General Charles W. Ryder’s 34^th Division and Major General Fred L. Walker’s 36^th Division), Lieutenant General C. W. Allfrey’s British V Corps (Major General W. E. Clutterbuck’s 1^st Division and Major General J. L. I. Hawkesworth’s 4^th Division or Major General D. A. H. Graham’s 56^th Division) and, in army reserve, Major General Matthew B. Ridgway’s US 82^nd Airborne Division.

The whole plan was cancelled on 20 July 1943 after the success of 'Husky' (i) rendered Sardinia superfluous to current Allied requirements, and the island was later occupied in 'Norman'.