The battle occurred as a result of an Indonesian effort to storm a British hilltop base at Plaman Mapu, on the border between the Malaysian state of Sarawak and Indonesia.

Dissent grew in military and political circles, particularly over the perceived foolishness of incumbent President Sukarno in continuing the conflict, and on 30 September elements of the army revolted against him.

The British government, in their reorganisation of the region following their departure, sought to combine Malaya with Singapore and the states of Sarawak, North Borneo, and Brunei to form a new 'Malaysian Federation.'

Sukarno, who was leaning ever closer towards the Communist bloc of China and Russia, despised the 'imperialist' British, and had planned to incorporate the latter three regions, all of which are located on the northern tip of Borneo, with the Indonesian-controlled territory of Kalimantan, which makes up the vast majority of that island.

Sukarno determined to begin a military Confrontation with Malaysia, which through a series of raids and supported revolts might improve Indonesia's position in negotiating for the island.

Sukarno's choice of pursuing this strategy would come at the expense of an important program aiming at the rehabilitation of the damaged economy, as it relied upon funding from Britain and America, who would not support the strengthening of another Communist power forming in Asia.

However, the Indonesian populace and much of the government, who had recently fought their way from the hands of Dutch rule, would likely not support the economic program as it would seem as if Indonesia was sliding back into the embrace of the 'imperialist' powers of the West.

The proposal selected as the most effective was presented to the Cabinet in January 1964 by Richard Austen Butler, who recommended that Britain continue fighting without declaring war, with the conflict contained in Borneo, a strategy designed to weary the Indonesians of battle until the necessity of economic reform overcame them and peace was made.

[5] The actual implementation of this strategy was left to the commander on site, Major General Walter Walker, a veteran of the Burma Campaign of the Second World War who had learned the hard lessons of the Malayan Emergency.

Walker ordered that one-third of a unit should be left defending its base, which would be one of many along the border, while the remainder patrolled the jungle, foraying into Indonesian territory and attempting to keep them tied down at their headquarters instead.

This involved elite British light infantry roaming the jungle, attacking Indonesian bases and patrols at will and trying to give the appearance of being everywhere at once for psychological effect upon the enemy.

Walker continued the Claret raids to great effect until the end of his tenure, being replaced by Major General George Lea as commander of British forces in Borneo.

Due to the intensity of recent fighting, the base commander, Lieutenant Colonel Ted Eberhardie, had only been able to spare a few of the new men for a training course in such combat at Singapore, but one of those was Sergeant Major John Williams, who would play a crucial role in the coming battle.

Ample evidence of the coming attack was discovered by British patrols, but signs of enemy troop movements were disregarded and newly cleared positions were mistaken for ambush sites.

As a result of these conditions, only 36 men were present in the base in the early morning hours of 27 April 1965 when it came under ferocious attack by 150 to 400[11] Indonesian troops, supported by artillery and rocket fire.

A shell landed among the group and wounded half of them, but Williams and the remainder engaged at least thirty Indonesian infantry who had been firing into the base from the trench in vicious hand-to-hand combat and managed to push them from it with minor casualties.

This defence was remarkably effective, and eventually the barrage of Indonesian rocket fire halted and the few remaining British soldiers rose from their hideouts and began to clear the perimeter.

Defeat in what was intended to be a highly publicised victory helped to break the fracturing patience of the army generals on the right and unite them against what they now saw to be the destructive force of Sukarno and the Communist Party.

[18] The army blamed the revolt on the Communists, and excited an anti-leftist fervour among the populace that contributed to the subsequent anti-Communist Purge, where high-ranking members were executed along with hundreds of thousands of suspected collaborators with millions imprisoned.