The Defeat of the British

The Imperial Guards started to move down to their target. On 11th February was Kigensetsu, the anniversary celebration of the coronation of Emperor Jimmu, the day Yamashita had hoped to capture Singapore. Ammunition supplies were running low for the Japanese forces. he had letters dropped over HQ Malaya Command areas, urging Percival to give up his desperate fight, thus hoping for an early surrender.
With the rapid Japanese approach, Percival moved his HQ to the underground Fort Canning Bunker, also known as the Battlebox. It was here he made the decision to surrender four days later.
The defending troops were badly shaken. Thousands of exhausted and frightened stragglers keft the fighting to seek shelter in large commercial buildings.
On 13th February, Yamamashita moved his HQ to the Fort Motor Factory, apparently bomb-damaged. He feared a prolonged war once Percival had dug in at his last defensive position and wait for reinforcements. he had not enough men and ammunition for a long war.
Thus, he tasked the 18th Division to capture the Alexandra Barracks and the Imperial Guards to capture Macritchie before Percival had settled in his lst stand.
14 February dawned bitterly on the defending forces. The 18th Divison started their assault on the hapless Malay Regiment and the Imperial Guards swarmed out of MacRitchie to fight the British.
15th February was the day the British surrendered. Percival had a choice - a counterattack to wrest back MacRitchie Reservior to restore the water supply and retake food depots or surrender. Due to the massive depletion of supplies, his commanders opted for surrender.
Percival went to the Japanese HQ at Ford Motor Factory and originally requested for a stall of time. However, Yamashita demanded an immediate unconditional surrender, or a massive assualt on Singapore. Percival eventually gave in and signed the surrender document.