During the 1920s many revolutionary groups reorganised their underground activities, while many continued working under the Congress, thus getting access to the masses and providing an organisational base to the Congress in towns and villages. Many cooperated with C.R. Das in his Swarajist work. After Das’s death (1925), the Bengal Congress broke up into two factions—one led by J.M. Sengupta (Anushilan group joined forces with him) and the other led by Subhash Bose (Yugantar group backed him).
The actions of the reorganised groups included an assassination attempt on the notorious Calcutta Police Commissioner, Charles Tegart (another man named Day got killed) by Gopinath Saha in 1924. The government, armed with a new ordinance, came down heavily on revolutionaries. Many including Subhash Bose were arrested. Gopinath Saha was hanged.
Because of government repression and factionalism among the revolutionaries, revolutionary activity suffered a setback, but soon many of revolutionaries started regrouping. Among the new ‘Revolt Groups’, the most active and famous was the Chittagong group under Surya Sen.
Surya Sen had participated in the Non-Cooperation Movement and had become a teacher in the national school in Chittagong. He was imprisoned from 1926 to 1928 for revolutionary activity and afterwards continued working in the Congress. He was the secretary of the Chittagong District Congress Committee. He used to say ”Humanism is a special virtue of a revolutionary.” He was a lover of poetry and an admirer of Tagore and Qazi Nazrul Islam.
Surya Sen decided to organise an armed rebellion along with his associates—Anant Singh, Ganesh Ghosh and Lokenath Baul—to show that it was possible to challenge the armed might of the mighty British Empire. They had planned to occupy two main armouries in Chittagong to seize and supply arms to the revolutionaries to destroy telephone and telegraph lines and to dislocate the railway link of Chittagong with the rest of Bengal. The raid was conducted in April 1930 and involved 65 activists under the banner of Indian Republican Army—Chittagong Branch. The raid was quite successful; Sen hoisted the national flag, took salute and proclaimed a provisional revolutionary government. Later, they dispersed into neighbouring villages and raided government targets.