The offensive reversed the United Nations Command (UN) advance towards the Yalu River which had occurred after their intervention in the wake of the North Korean invasion of South Korea at the start of the war.

To halt the PVA advance, the 27th British Commonwealth Brigade was ordered to defend the lower crossings of the Taeryong and Chongchon rivers as part of a rearguard, in conjunction with the US 24th Infantry Division further upstream on the right.

In their first battle with the PVA, the 3rd Battalion, Royal Australian Regiment (3 RAR) captured a well defended hill with only limited offensive support, and held it in the face of heavy counter-attacks before confused command decisions resulted in a disorganised night withdrawal while still in contact.

The withdrawal threatened to open the 27th British Commonwealth Brigade's left flank and the Australians were ordered to immediately reposition on the ridge, yet ultimately it was too late to regain the feature in darkness.

Nonetheless, the 27th British Commonwealth Brigade succeeded in preventing a PVA break-through at Pakchon, keeping open vital withdrawal routes across the river and securing the UN left flank.

[3] Numerically superior and better-equipped, the KPA crossed the 38th Parallel and rapidly advanced south, easily overcoming the inferior Republic of Korea Army (ROK).

As such, with a strength of nearly 1,000 men, the addition of 3 RAR gave the brigade increased tactical weight as well as expediently allowing the Australians to work within a familiar organisational environment, rather than being attached to a US formation.

[12] By the time 3 RAR arrived in the theatre, the KPA had been broken and were in rapid retreat, with MacArthur's forces conducting a successful amphibious assault at Inchon and breakout from the Pusan Perimeter on the southern tip of the Korean peninsula.

[17] The advance continued north with little respite, and on 22 October the Australians fought their first major action at Yongju, killing 150 KPA and capturing 239 of the brigade's 800 prisoners, for the loss of seven men wounded.

On 24 October, MacArthur had removed all restrictions on the movement of his forces south of the Yalu River and prepared for the final phase of the advance, defying a directive of the US Joint Chiefs of Staff and risking Chinese intervention in support of North Korea.

[21] With the war considered all but over the 27th British Commonwealth Brigade continued to pursue the KPA towards Chongju; however, the advance increasingly encountered strong resistance as they approached the Manchurian border.

[29] 3 RAR remained at Chongju, however, due to a lack of transport, while the remainder of the brigade moved south; now the most forward element on the US Eighth Army's left flank, the battalion soon became isolated without communications or armour and artillery support.

[36] To halt the PVA advance, the 27th British Commonwealth Brigade was ordered to defend the lower crossings of the Taeryong and Chongchon rivers as part of a rearguard, in conjunction with the US 24th Infantry Division further upstream on the right.

[31] The Middlesex occupied the town and the high ground to the north and east, while 3 RAR and the Argylls held positions covering the western approaches to the Taeryong, with the latter designated as the brigade reserve.

[44] Coad considered that unless the PVA could be cleared from the gun position and the hills secured, the brigade was in danger of being surrounded and cut off and the crossing at Anju lost, while US 19 RCT would also be threatened.

[46] Meanwhile, to the north, under the command of Captain Howard M. Moore, C Battery, US 61st Field Artillery formed its six 105 mm M2A1 howitzers into a semi-circle and created a perimeter around them, strongly defending their positions with automatic weapons from behind their gun shields.

[46] One of the American howitzers was depressed and brought into action, firing over open sights at point-blank range, bouncing shells off the frozen paddy fields which then exploded among the assaulting troops.

Running low on small arms ammunition and having lost one howitzer destroyed as well as two men killed and seventeen wounded, the Americans faced the prospect of being overrun.

Back in action, the guns from C Battery also fired in support of the British infantry, and after a vigorous engagement in which Gordon-Ingram was wounded the PVA were compelled to withdraw, leaving many of their dead on the road.

[51][52] Throughout the morning a United States Air Force (USAF) LT-6G Mosquito light observation aircraft had continued to monitor growing concentrations of PVA in hills to the rear of the 27th British Commonwealth Brigade, with reports indicating their strength at approximately one division.

[60] PVA mortars and machine-gun fire continued to fall on 3 RAR, and at 17:00 a round destroyed the A Company headquarters, killing two men and wounding four others, including Chitts who was evacuated by stretcher.

Meanwhile, as the light began to fade the administrative elements of the formation and the US 61st Field Artillery Battalion were moved south of the Chongchon River amid a bitter wind.

[64] The decision proved to be a serious tactical error, for as was to be demonstrated often in the months that followed, the PVA were skilled at moving across the hills to outflank road-bound UN forces who often failed to hold the ridges on either side of the roads only to be confronted by strong concentrations in front and behind them as a result.

[32] The withdrawal threatened to open the 27th British Commonwealth Brigade's left flank; recognising the danger this posed, Coad ordered Walsh to immediately reposition his companies on the ridge.

At 22:00 Coad arranged to shell and mortar the relinquished ridge, while a standing patrol from the Middlesex was posted on the south-western side of the Maenjung-dong pass in anticipation of a renewed PVA attack.

[67] A number of officers of the battalion were later critical of the decision to withdraw while still engaged, believing that it had been both dangerous and unnecessary, while the lack of detailed planning, reconnaissance and orders were also seen as a factor in the disorganisation that ensued.

[64] The same day Coad visited 3 RAR; dissatisfied with the battalion's dispositions and having now lost confidence in its commander, he relieved Walsh of his position, appointing the second-in-command, Major Bruce Ferguson, in his place.

[73] In their first battle with the PVA, 3 RAR had successfully captured a well defended hill with only limited offensive support, and had held it the face of heavy counter-attacks before confused command decisions resulted in the battalion conducting a disorganised night withdrawal while still in contact.

[32] Nonetheless, the 27th British Commonwealth Brigade had succeeding in preventing a PVA break-through at Pakchon, keeping open vital withdrawal routes across the river and securing the UN left flank.

[80] On 9 November the advance wheeled to the north-west around Pakchon, with 3 RAR moving forward another 3 kilometres (1.9 mi) to the east, encountering little resistance and taking a number of prisoners in the process.