On January 25, 1952, the British attacked an Egyptian police barracks at Ismailiya (Al Ismailiyah) when its occupants refused to surrender to British troops. Fifty Egyptians were killed and 100 wounded.

The January incident led directly to "Black Saturday," January 26, 1952, which began with a mutiny by police in Cairo in protest against the death of their colleagues. Concurrently, groups of people in Cairo went on a rampage. British property and other symbols of the Western presence were attacked. By the end of the day, 750 establishments valued at £50 million had been burned or destroyed. Thirty persons were killed, including eleven British and other foreigners; hundreds were injured.

The British believed there was official connivance in the rioting. Wafdist interior minister Fuad Siraj ad Din (also seen as Serag al Din) was accused of negligence by an Egyptian government report and dismissed. The king dismissed Nahhas, and four prime ministers held office in the next six months. It became clear that the Egyptian ruling class had become unable to rule, and none of the radical nationalist groups was strong enough to take power. This power vacuum gave the Free Officers their opportunity.