Singapore's bilingual policy was established to help its people appreciate their cultural roots, but the country's founding fathers also believed that everyone must go beyond their own communities to build a common national identity, Deputy Prime Minister Heng Swee Keat said yesterday.

He noted that the policy was established in 1966 - a time of turbulence and social unrest in Singapore.

"Bilingualism has to be viewed in the context of the values we hold dear as a society - that regardless of race, language or religion, we can build a fairer and more just society, living harmoniously together, and progressing as one united people. This is the distinctive feature of our Singapore identity," he said.

Mr Heng, who is also Coordinating Minister for Economic Policies, was speaking as the guest of honour at Dunman High School's 65th anniversary celebration at the school's campus in Tanjong Rhu.

Race and religion will always be a work in progress, he added.

"Looking at the divides in many societies around the world, embracing diversity and living harmoniously together is not the natural order of things," he said.

He added that recent incidents of racial and religious tensions serve as a reminder that Singapore's harmony can be lost easily if Singaporeans are not careful.

"We must proactively grow what we have in common, even as we become more diverse as a society," he said.

Mr Heng also spoke about Dunman High's heritage as one of the first Special Assistance Plan (SAP) schools. Dunman High is one of the nine schools selected by the Ministry of Education in 1979 to transition from Chinese-medium schools to bilingual institutions under the SAP.

He said: "Since then, the school has gone on to become an educational institution with strong bilingual traditions and a deeper appreciation of the Chinese culture.

"It is interesting that a Chinese-medium secondary school adopted the name of an English gentleman - our first commissioner of police, Sir Thomas Dunman - who probably spoke no word of Chinese."

The school's first permanent campus was in Dunman Road, from which the school took its name.

Also speaking at the event - on a Zoom call from Switzerland - was the chairman of Dunman High's school advisory committee Ng Ser Miang, who spoke about the school's growth and how it first operated in a borrowed campus in Mountbatten Road.

"It is heartening to see the solid foundation past principals, teachers and students have built continue to strengthen and solidify. As an old boy, it warms my heart to see that the school's motto continues to be the guiding principle of Dunman alumni today."

Dunman High was founded in 1956 as the Kallang West Government Chinese Middle School. Before the Dunman Road campus was built, the school was loaned a primary school campus in Mountbatten Road. The school's motto is "Honesty, trustworthiness, moral courage and loyalty", usually written in Chinese characters.

The celebration also featured a video of a wushu performance accompanied by a Chinese orchestra performance, both by Dunman High students.

About 200 alumni tuned in from around the world via Zoom to sing Happy Birthday to the school.

Mr Heng also spoke about the good that Dunman High students have been doing in the community amid the pandemic.

He cited how several Dunman students had come together to record a performance of two songs in Tamil for foreign workers warded in Singapore.

He said: "They sang, played the erhu, guzheng, flute and drums, recorded their performance over Zoom, and edited the recordings to create a video.

"This display of concern also showed how your students contribute to strengthening multiculturalism and racial harmony."