Short answers, pulled from the story.
The Battle of Singapore was fought from the 8th to the 15th of February 1942 during the Second World War. British Lieutenant-General Arthur Percival formally surrendered to Japanese General Tomoyuki Yamashita at the Ford Motor Factory shortly after 17:15 on the 15th of February.
About 80,000 British, Indian, Australian, and local troops became prisoners of war at Singapore, joining approximately 50,000 already captured during the earlier Malayan campaign. Churchill described it as the largest surrender in British history.
Britain lost Singapore due to a combination of faulty intelligence, misplaced defences, and command failures. Percival concentrated his best forces on the north-east of the island expecting a landing there, while the Japanese attacked the weakly defended north-west. Communication breakdowns, premature withdrawals by Allied commanders, and an overall failure of the pre-war Singapore strategy compounded the defeat.
Yamashita commanded just over 30,000 men from three divisions at Singapore. Percival had approximately 85,000 men, though around 15,000 were administrative personnel and many units were under-strength, inexperienced, or newly arrived.
On the 14th of February 1942, Japanese troops entered the Alexandra Barracks Hospital, killing up to 50 soldiers including some undergoing surgery, as well as doctors and nurses. The following day, about 200 bound male staff members and patients were marched to an industrial area where most were bayoneted. Private Arthur Haines of the Wiltshire Regiment later wrote a four-page eyewitness account of the massacre.
The fall of Singapore severely undermined British prestige in Asia and, according to author Alan Warren, shattered the British Empire's illusion of permanence and strength, making European empires in Asia unsustainable and presaging the end of colonialism in the region after the war. Singapore has marked the anniversary of the surrender every year since 1998 as Total Defence Day on the 15th of February.