Jaafar and Tunku Abdul Rahman at a time of imminent constitutional changes in the country. Strongly anti-communist, he was also trusted by the British colonial officials. He joined the Malay leaders – first through the All-Malaya Council of Joint Action, which he chaired, and then the Communities Liaison Committee headed by Dato' Sir E. E. C. Thuraisingham – to fight for constitutional change and work towards inter-ethnic co-operation. Tan organized a hartal (general strike) in Malacca to protest against the British colonial government. The establishment of the Federation of Malaya did not go down well with the ethnic Chinese, whereby favourable conditions for obtaining citizenship for the Chinese and other non-Malays were withdrawn. The Malaysian Chinese Association (MCA) was formed in 1949 under the leadership of Tan Cheng Lock who frequently raised grievances over the citizenship terms that were set when the Federation was established. As a result, communal tensions between the Malays and Chinese surfaced, and Onn Jaafar, who was then heading UMNO kept his distance from Tan. Tan encountered initial difficulties with meeting Sultan Ibrahim of Johor, who was not accustomed to working with Chinese businessmen. The goal for the foundation of the Malayan Chinese Association was to unite the Chinese population in Malaya, including the protection of the rights and interests of the Chinese, also to work with the colonial government to stop the spread of communism and to work with other races to achieve the independence of Malaya. The MCA branches had been set up after their campaigns had attracted more than 200,000 members. Soon later, on 26 September 1951, he had supported the idea of Onn Jaafar to form the Independence of Malaya Party (IMP) in Kuala Lumpur with co-operation of various races as her theme of struggle. However, the formation was choppy, which due to the fact that Dato' Onn Jaafar was not co-operative on the issue of citizenship. In the end, Tan decided that only a Chinese party could safeguard the interests of his community and that multi-ethnic co-operation was more likely to be achieved through partnership with UMNO. With that, the MCA joined with UMNO to form the Alliance, the precursor to the Barisan Nasional. However some people do not agree that he acted in best interest of Malaysian Chinese as some felt that the marginalization of Malaysian Chinese would not be so severe had the British ruled until now citing Hong