Boonchu was being treated at Vichaiyudh Hospital and was pronounced dead at 6am yesterday.

His family will hold a funeral service for him at Wat Nongkae, Hua Hin, Prachuab Khiri Khan, between now and March 25.

Boonchu was one of the first generation of bankers who entered politics in the 1970s. With his colourful ideas and deep pockets, he quickly became a domineering force in Thai politics.

He joined the Social Action Party and served as a top aide to the late MR Kukrit Pramoj. During the brief reign of the Kukrit government between 1975 and 1976, Boonchu came to be known as an "economic tsar".

One of his most controversial policies was to inject money into the rural sector in order to boost standards of living. Several billion baht of government money - or ngern phan (money allocation) - was poured into five thousand tambon councils. But this populist policy had only a short-term impact.

The Bt1-million village fund organised by Thaksin Shinawatra's government and other populist policies were not original ideas as they came much after than Boonchu's ngern phan.

Born on January 24, 1922, in Chon Buri, Boonchu was the eldest of five children. His family, of Chinese Hainan origin, was quite poor. His father worked as a carpenter.

However, he was a bright student. He entered Thammasat University and graduated with a degree in accounting. Afterward, he opened his own accounting firm.

When the late Chin Sophonpanich, father of Chatri Sophonpanich, became interested in acquiring Bangkok Bank, he brought in Boonchu. At that time Bangkok Bank was facing a liquidity crisis. Boonchu, a keen accounting man, helped to improve the bank's assets.

Eventually, he rose to become president of Bangkok Bank and played a key role in the expansion of its branches nation-wide.

But Boonchu became hooked on politics. He was appointed a senator during the premiership of Sanya Thammasak. He played a role in drafting the constitution in 1974, which laid the groundwork for political parties to prosper.

He joined the Social Action Party, where he enjoyed the best days of his political career. In the 1975 election, the Democrat Party garnered 72 MP seats, compared with only 18 for the Social Action Party. The late Seni Pramoj, who was head of the Democrats, became prime minister. But he resigned a few months later.

Kukrit Pramoj succeeded his elder brother as prime minister on March 17, 1975, with a tiny margin. Boonchu, the economic tsar, set his sights on tackling Thailand's long-term economic problems and the pressing turmoil in April that year. He introduced Thailand's first ever populist policy by injecting money into the tambon councils, creating a big fanfare in Thai politics.

Afterward, he was less successful due to sharp political conflicts. Boonchu decided not to run in the election in 1983 and returned to banking. He served as chairman of Siam City Bank.

But the lure of politics was too strong and Boonchu returned as head of the Kijprachakhom Party in the 1986 election. His party mustered 15 seats, but was unable to become a partner in the coalition government. The following year his political stature was undermined by the resignation of five of the party's MPs.

After the 1988 election, Kijprachakhom Party joined with other parties to form the Ekaphap Party under the leadership of Narong Wongwan. Boonchu served as a deputy head and Chalermphand Srivikorn as secretary-general. Boonchu was responsible for the party's policies on economic affairs.

Towards the end of his political career, Boonchu saw his stature dwindling. He joined the Democrat Party, serving as an adviser to Chuan Leekpai, who was prime minister in 1993.

His political motto was memorable. "The future of a political party hinges on its policies. Any inappropriate policies will just simply fade away."

The 1997 financial crisis hit Boonchu's family hard. But it has managed to move on and they invested in the successful Chiva-Som Resort and Spa, a wellness resort centre in Hua Hin that has become world renowned.