Japanese tanks and infantry smashed through the undefended streets of Jitra with the loss of only about 25 men. They quickly took the airfield of Alor Star, where they found porridge still warm in the RAF officers' mess. Bomb stores and aviation fuel were captured intact and are said to have been used by the Japanese Air Force to attack the retreating British. Enemy air activity became relentless.
According to the 137 Regt War Diary, 501 Battery was in action supporting the defence of RAF Alor Star. By 16th December, says the the diary, 501 Battery was at the Heawood rubber plantation, Bagan Serai. On 22nd and 23rd December the regiment withdrew further south, establishing its advanced and rear HQs respectively at the Kamunting and Tasek rubber estates, Chemor. On the road between Sungei Siput and Chemor, Lt Hartley's battery was dive-bombed. Four men were killed and six, including Lt Scott and Capt Mason, wounded. Two Morris Quads caught fire and a 25 pounder shell exploded. The Japanese aircraft dived lower than 100ft.
On 27/28th December 501 Battery was in position between Gopeng and Dipang. On 29th December it withdrew to the Bidor area via Kampar. The column was again dive-bombed and machine-gunned just south of Dipang. Five men were wounded. The last entry in the 137 Regt War Diary is for 31st December, 1941, Lt Hartley's 30th birthday, when his battery and the other two of 137 Regt were ail in the Bikam-Sungkai area.
The retreat is described by Harold Payne in his Imperial War Museum tape. He recalls the "humiliation" of Japan's complete air superiority. Men and vehicles were "sitting targets" on the single road. The men could take cover in the jungle, but not with their heavy guns and vehicles. The Japanese infantry were in hot pursuit. Mortar bombs were falling all around - "a nasty experience". The men weren't sure whether people in paddy fields were Malays or Japanese. Some appeared to be helping the enemy with bamboo stakes pointing to the British positions. "We shot them. That's war".
Payne recalls that the "most degrading" aspect of the campaign was the "total lack of air support". He describes as "stupid" the yellow paint of the British guns and vehicles, making them highly visible to the Japanese airmen.
By Christmas Day the Japanese held all Northwest Malaya including Butterworth and Penang (where a "Europeans only" evacuation order is still remembered locally).
The British regrouped at Kampar, on the Dipang River. There, in a four day battle notable for the effectiveness of the British artillery, presumably including Lt Hartley's 25-pounders, the Japanese suffered heavy casualties. The Ghurkas fought hand-to-hand with kukris. The Argylls repelled several attacks. The Sikhs carried out bayonet charges through machine-gun and mortar fire.
The British put up one of the hardest fights of the Malayan campaign at Kampar, but by 2nd January they were outflanked and the road to Singapore was cut off behind them. Under cover of intense artillery fire, in which presumably 501 Battery was engaged, they fell back along the main road to prepared positions at Trolak, about five miles in front of the Slim River.
Slim River "Everyone has heard of the battle of Slim River", says Harold Payne. The engagement was notable for the complete surprise achieved by a small force of Japanese tanks and infantry.
On 7th January at 0330 the Japanese overran the roadblocks and defences at Trolak, five miles north of the Slim River.
Half a dozen small Japanese tanks and a company of about 100 infantry in trucks then raced to the river, where the exhausted defenders, including Lt Hartley and 501 Battery, were caught completely off guard. They had not expected Trolak to fall so quickly and were given no warning that the Japanese were through. Payne records that a Japanese officer jumped out of a tank, drew his sword and severed the fuse to the bridge's demolition charges. Burt-Bnggs recalls meeting the officer, Lt Watanabe, at Tarsoa in 1943.
The tanks caught three battalions of 12 Brigade - two Gurkha and one of the 5/14 Punjab Regt - marching along the road and machine-gunned them. They caught 501 and 349 Batteries breakfasting by the roadside in the Cluny rubber estate, and shelled and machine-gunned them before they could get their artillery into position.
A British officer, Col Harrison, who arrived at the Cluny estate after the Japanese tanks had moved on, described the scene:
"The ammunition trucks and limbers were burning hard, shells were exploding and bullets crackling all over the place. I saw an ambulance bumping drunkenly over the broken ground until it hit a tree and overturned.
"A subaltern [Lt Hartley?] told me they had been breakfasting in the rubber 200 yards from the road when someone arrived and reported that tanks had broken through. Major Drought had dashed off to order two guns into action on the road but . . . five tanks arrived, halted on the road, and strafed the hide. . ."
Harold Payne recalls the decision to spike the guns - "a terrible thing for a gunnery officer to have to do". They abandoned all 13 guns which they had painfully got back from Jitra.
The Japanese took the Slim River road bridge at 0830hr before it could be demolished, cutting off the surviving defenders' escape road to the south.
When the CO of 137 Regt, Col Holme, Lt Hartley's commanding officer, was told about the Cluny estate action, he insisted on going back to help. He dashed off on a motor cycle and was never seen again.
The Slim River defeat, accomplished by a small Japanese force with total air superiority, effectively ended hopes of defending Malaya and Singapore.