On 8 December 1941, during the Second World War, the Japanese invaded Thailand, and crossed Pattani to invade British Malaya.
The Thai government, led by Marshall Plaek Phibunsongkhram became an active ally of Japan by promising to help Thailand retake some territorial claims back from the British and the French.
This included Sirat Malai, the former Malay dependencies of Kelantan, Trengganu, Kedah, and Perlis.
It is arguable that this move not only gave more territory to the Thai state but on the contrary, it strengthened the old Malay ties between the Pattani region and the northern Malayan peninsula states.

Tengku Mahmud Mahyuddin, a prominent Pattani leader and the son of the last Raja of Pattani, allied himself with the British in the hopes that Pattani would be granted independence after an Allied victory.
His main support came from ethnic Malays displeased by the nationalistic policies of the Phibun regime, which were seen by the southern Malays as forcing them to give up their own language and culture and the economic hardship that ensued as a result of alleged mismanagement.
According to Ockey, even leading Thai politicians such as Pridi Phanomyong, Seni Pramot were among those that "overtly or covertly" supported this resistance against the Japanese.
During this time the electoral seats for in this region were mainly held by non-Muslim representatives except Satun.
Mahyuddin assisted the British by launching guerrilla attacks against the Japanese.
In 1945, a petition by Malay leaders led by Tengku Abdul Jalal demanded that Britain guarantee independence for the southernmost provinces of Thailand.
At the war's end, the Greater Malay Pattani State (Negara Melayu Patani Raya) flag did fly briefly in Pattani.
However, since the British had no power over Thailand, the Thai continued to rule over Pattani, while the British kept Thailand stable as a counterweight to the communist insurgency in Malaya.
This led to the formation of several insurgent groups seeking the independence of Pattani.

After World War 2 had ended, the US had wanted to treat Thailand as an ally because of the resistance movement against the Japanese during the war but the British on the other hand had wanted to treat it as a defeated enemy.
With this notion in the balance, the newly elected government led by Pridi had to address the issue of the South.
With the aid of advisor Chaem Phromyong, a Muslim, the policies of accommodation and integration of the South.
With the closure of the war, the government also approved the Patronage of Islam Act.
This Act recognised the work and role of religious figures in the South and gave them authority once more in the affairs of the Muslims in that region.
Coincidentally, this Act also paved the way for Haji Sulong to become the president of the Pattani Islamic Committee in 1945.
It was from this appointment that Sulong began to take an interest in the restoration of the Islamic courts which had earlier been abolished by the Phibun regime.
Ockey had pointed out that Sulong was not entirely pleased with the restoration  process because the authority in the Islamic courts was still preceded by the presence of a judge from the Ministry of Justice alongside the Muslim judge in cases.
However, the negotiations over this supposed unhappiness was in the form of meetings to discuss terms and not open confrontation.
This peaceful attempts at resolution would all come to an end in November 1947 when Pridi was forced out of power by opposing army personnel.
On 8 December 1941, during the Second World War, the Japanese invaded Thailand, and crossed Pattani to invade British Malaya. The Thai government, led by Marshall Plaek Phibunsongkhram became an active ally of Japan by promising to help Thailand retake some territorial claims back from the British and the French. This included Sirat Malai, the former Malay dependencies of Kelantan, Trengganu, Kedah, and Perlis. It is arguable that this move not only gave more territory to the Thai state but on the contrary, it strengthened the old Malay ties between the Pattani region and the northern Malayan peninsula states.
Tengku Mahmud Mahyuddin, a prominent Pattani leader and the son of the last Raja of Pattani, allied himself with the British in the hopes that Pattani would be granted independence after an Allied victory. His main support came from ethnic Malays displeased by the nationalistic policies of the Phibun regime, which were seen by the southern Malays as forcing them to give up their own language and culture and the economic hardship that ensued as a result of alleged mismanagement. According to Ockey, even leading Thai politicians such as Pridi Phanomyong, Seni Pramot were among those that "overtly or covertly" supported this resistance against the Japanese. During this time the electoral seats for in this region were mainly held by non-Muslim representatives except Satun. Mahyuddin assisted the British by launching guerrilla attacks against the Japanese. In 1945, a petition by Malay leaders led by Tengku Abdul Jalal demanded that Britain guarantee independence for the southernmost provinces of Thailand. At the war's end, the Greater Malay Pattani State (Negara Melayu Patani Raya) flag did fly briefly in Pattani. However, since the British had no power over Thailand, the Thai continued to rule over Pattani, while the British kept Thailand stable as a counterweight to the communist insurgency in Malaya. This led to the formation of several insurgent groups seeking the independence of Pattani.
After World War 2 had ended, the US had wanted to treat Thailand as an ally because of the resistance movement against the Japanese during the war but the British on the other hand had wanted to treat it as a defeated enemy. With this notion in the balance, the newly elected government led by Pridi had to address the issue of the South. With the aid of advisor Chaem Phromyong, a Muslim, the policies of accommodation and integration of the South. With the closure of the war, the government also approved the Patronage of Islam Act. This Act recognised the work and role of religious figures in the South and gave them authority once more in the affairs of the Muslims in that region. Coincidentally, this Act also paved the way for Haji Sulong to become the president of the Pattani Islamic Committee in 1945. It was from this appointment that Sulong began to take an interest in the restoration of the Islamic courts which had earlier been abolished by the Phibun regime. Ockey had pointed out that Sulong was not entirely pleased with the restoration  process because the authority in the Islamic courts was still preceded by the presence of a judge from the Ministry of Justice alongside the Muslim judge in cases. However, the negotiations over this supposed unhappiness was in the form of meetings to discuss terms and not open confrontation. This peaceful attempts at resolution would all come to an end in November 1947 when Pridi was forced out of power by opposing army personnel.
Patani