President Tony Tan Keng Yam leaves office this Thursday as the head of state who preceded the biggest change to the elected presidency in its 26 years.

The move to entrench multiracialism in the highest office in the land, by ensuring members of the country's main races occupy it periodically, is a change he fully supports.

He believes it will stand the nation in good stead and further fortify the social fabric at a time when the terror threat to Singapore is at its highest.

Citing the spate of recent terror attacks and disrupted terror plots around the world, he says: "Singapore is a target for terrorists."

In a measured voice, he adds: "One of these days, an incident will happen. And when that happens, it's very important to ensure we do not allow it to destroy our cohesion, or to have tensions between the various communities.

"In that respect, reserving this next election for the Malays is appropriate - unfortunately, because of these circumstances around the world which Singapore is caught up in," he says.

For Dr Tan, 77, the need for Singapore to continue reinforcing multiracialism is never-ending.

It is a key reason he cited for supporting the reserved election when the Constitutional Commission proposed the mechanism last year.

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"Since the elected presidency was instituted, the presidents, including myself, have all been non-Malays," he adds in an interview at the Istana's Yusof Room, where a bust of the first president, Mr Yusof Ishak, who died in office in 1970, is displayed.

"It's good to make sure from time to time, people of different ethnic groups have the opportunity to become president so that it reflects our multiracial society," he says.

Indeed, ensuring Singapore stays multiracial and the bonds that bind its diverse people grow stronger each day are aspirations especially close to the President's heart.

During the 75-minute farewell interview with The Sunday Times and sister newspapers Lianhe Zaobao and Berita Harian late last month, he repeatedly stresses the need to constantly tend to the social fabric, to build up what he calls the country's "social reserves".

These reserves include mutual trust and understanding developed over the years by Singaporeans of different backgrounds, which has helped cement inter-racial and inter-religious harmony, he says.

But out-of-the-ordinary incidents, like the Little India riot on Dec 8, 2013, demonstrate how fragile this state of affairs could be.

Dr Tan was abroad when he got news on the scale of the riot by foreign workers from the Indian sub-continent.

"I was alarmed," he recalls. The violence and burning of police cars - scenes reminiscent of the communist and race-instigated riots of the 1950s and 1960s - worried him.

REWARDING WORK I've done my best. It's been hard work but it's always been very rewarding. How Singaporeans will regard me, that's for Singaporeans to decide.'' PRESIDENT TONY TAN KENG YAM, on his assessment of his six-year term in office.

"If it gets out of hand, it could cause great strain on our social fabric," he says, recalling his anxiety.

He felt it would be good for the President to make a statement "to emphasise the need for calm, for people not to take matters into their own hands and reinforce the importance of racial harmony".

"We should not let a single incident such as this undermine confidence in our society," he wrote in a Facebook post soon after the incident. "Instead, let us redouble our commitment to keeping Singapore safe, peaceful and strong."

Dr Tan recalls in the interview: "We have no SOP (standard operating procedure) for this sort of thing because we never thought this could happen in Singapore. But when it arises, you have to decide whether you should just sit back or whether that's an area (in which) you could make a contribution."

Singapore's multiracial harmony and peace are very fragile, he notes.

"You have to keep emphasising it and it's not something which is to be taken for granted," Dr Tan says.

MULTIRACIAL HARMONY IS KEY

Dr Tan came to the job after a quarter-century of public service and in an election that he won by a whisker: 7,382 votes.

During the 2011 campaign, the call by some for the president to be an alternative centre of power was not only insistent but reflected a widespread misunderstanding of the role of the elected president.

In his characteristic calm voice, Dr Tan describes the president's role and responsibilities, making clear the job of governing the country is that of the Government, not the president.

On the presidency and today's young Q What are your reflections on the presidency as you approach the end of your term? A The president has a very important role domestically. As head of state, he's a unifying force. He has to build a sense of community, a cohesive society, where people help each other, look out for each other, are concerned for each other. This is more important than ever in these difficult times when we have problems of radicalisation and extremism. I've met many voluntary welfare organisations and social groups to try and understand their different concerns in order to explain some of the major changes in Singapore - for example, our demographic changes and how technology is disrupting our economy. Singapore is an ageing society and that has vast implications for our organisation of social services. Health spending will go up, government spending will go up. Q What are your views on today's youth and how confident are you of their capacity to take Singapore forward? A Every generation is different. Our younger generation grew up in a very different world from the previous generation in the sense that Singapore has done well over the last 50 years. They have had a comfortable livelihood. But I'm very impressed with their energy, in that they are able to fend for themselves. For example, it is unusual for anybody nowadays to take a job when he or she finishes school or university and remain in one job for life. So being resilient, looking forward, lifelong education, being prepared for change - these are important areas our young people need to absorb. And talking to them, I take heart and am encouraged by their enthusiasm and confidence. I look forward to Singapore being in their hands. I'm sure they will do a good job. Maybe not in the same way the previous generation would have done it, but things must change, we have to change with the times. Q There have been a number of spoofs about you. One is of you as Colonel Sanders of KFC. How do you react to them? A Some are amusing, some less so. As long as it's not defamatory, you have to take it in your stride. I won't say it's comfortable, but what can you do? They have all been done in reasonably good spirit. People are amused and I try not to get too excited over that. You can't keep on being angry about all of this. There's no end to it. Q Looking back at these six years, did you make any conscious effort to distinguish yourself from your predecessors? A Every president has got his own style, his preoccupations. The circumstances were different in each term. I don't think it's a battle. You can't change yourself. You have to be yourself. Each of us is made up of a complex combination of personality, behaviour, likes and dislikes, what you're concerned with, and it is for each president to define his or her role and then to work out the priorities. The president has to set out his own style. Q What do you think Singapore can expect from the next president? A I am sure there will be a suitable candidate who will do a good job. Singaporeans should choose wisely, look at their background. Q Any advice for your successor? A That would be presumptuous. Each president has his or her own priorities and strengths, and will have to use that as well.

But as head of state, the president can build a sense of community and a cohesive society.

This thinking underlies his active support for various causes to help the less fortunate and encourage volunteerism, among others.

It also explains his Facebook posts to remind Singaporeans that racial harmony and understanding are fundamental to the nation's stability and progress when incidents, like the arrests of radicalised Singaporeans in June this year, happen.

As many leaders here and overseas have, Dr Tan reiterates: "Islam is a religion of peace and all the violence propagated falsely in its name is not Islam."

Islamophobia - or hateful sentiments towards Muslims that have gained ground in other societies - unsettles him too and he feels its spread is "very, very dangerous".

The scourge of terrorism and its impact on communities elsewhere is an issue Dr Tan has intimate knowledge of. He was deputy prime minister and defence minister back in 2001, when the Government uncovered home-grown terror cells that were part of regional network Jemaah Islamiah. And two years ago, he was the target of a young Singaporean radicalised by the Islamic State in Iraq and Syria. The youth had planned to go to an Istana open house and kill the President if he could not go to Syria.

Dr Tan reminds Singaporeans that such cases should not lead to fear and suspicion that drive a wedge between communities.

He notes that the Malay-Muslim community has taken progressive steps to counter radicalism.

Foreign leaders he meets are keen to find out how Singapore maintains multiracial harmony and what role is played by the Malay-Muslim community.

He credits the community for its response, saying: "A large part is due to the way the Malay community has reached out to other communities as well." The progress the community has made and continues to make "can be a source of pride for all Singaporeans", he adds.

BRINGING PRESIDENCY CLOSER TO THE PEOPLE

Educating people about the presidency and explaining its unique evolution in Singapore have also been a key effort of Dr Tan's during his time in office.

It led him to initiate the formation of the Istana Heritage Gallery in Orchard Road to make the Istana more accessible and highlight the president's other critical roles - the ceremonial, like leading the nation in major celebrations and representing it abroad; and the custodial, which involves safeguarding the reserves as well as the integrity of the public service.

He also initiated guided tours of the Istana and its grounds for the public during the five open houses a year. "They are helpful in demystifying the presidency and making people more aware of its role," he says.

"The president has the right to be informed, but the Government is actually the one that sets out the initiatives, that runs the country daily," he adds.

His slim victory, a result of the unsettled state of the ground in the wake of the May 2011 General Election, led Dr Tan to declare, when he was sworn in as Singapore's seventh president, that it would be his "most challenging appointment in three decades of public service".

He pledged to reach out to all Singaporeans, whatever their political persuasion.

It is manifested, among others, in his frequent meetings with cultural and community groups, the Istana Heritage Gallery and his active presence on social media.

In Facebook posts, he would recount his public events and offer a voice of reassurance in the wake of terror arrests, and offer comfort during tragedies like the bus crash in Muar on Christmas Eve last year, when Singaporeans were killed.

One area he is heartened by is how ethnic self-help groups work together on joint activities for those in need, regardless of race.

"This helps show this is what Singapore is - despite our different communities, we all work and walk together and share common aspirations, and we can help other people together. It's an achievement we have to carry on," he says.

Dr Tan's presidency coincided with several eventful milestones that brought Singaporeans closer. These include Singapore's Golden Jubilee festivities, its first Olympic gold medal and the death of founding prime minister Lee Kuan Yew.

TAKING PRESIDENTIAL ADVISERS TO PUNGGOL

However, a very important function of the presidency that is hardly carried out in public view is the custodial role.

Dr Tan says he spends "a lot of time" on it: from reading information papers and briefs from government agencies to discussing fiscal matters touching on Singapore's reserves with the Council of Presidential Advisers (CPA).

Under the Constitution, the president holds the second key to the national reserves, accumulated in previous terms of government.

These include deposits with the Monetary Authority of Singapore and assets managed by GIC and Temasek Holdings. No official figures have been made public, but the reserves are valued at several hundred billions of dollars.

Dr Tan, a former executive director and deputy chairman of GIC, notes that as a country with no natural resources, "our reserves are the only asset which will see us through a crisis or a difficult time".

The CPA, which was expanded this year from six members to eight members, meets him very often, Dr Tan says. "They give me their views, I join them at meetings with ministers. And they always give me their recommendation on proposals from the Government or the appointment of senior officials."

Several long-term issues also feature in his discussions with the CPA and the Government. These include large-scale infrastructure projects, such as the expansion of Changi Airport and the seaport, the Kuala Lumpur-Singapore High Speed Rail and the expansion of the MRT network.

"This would take not one term of government, but many terms. You have to study ahead and see how these can be financed in different ways," he says.

Dr Tan previously noted that he has had a harmonious working relationship with the Government, which keeps him informed of all its major decisions. In a statement to Parliament last year, ahead of its debate on changes to the elected presidency, he said: "On a regular basis, the Prime Minister and I meet over lunch and on other occasions, for him to brief me on his preoccupations and intentions, and to exchange views on the strategic direction in which Singapore is heading.

"Our relationship is built on mutual trust and respect. This, to me, is key to the effective functioning of our system," he said then.

Giving his assent to the Government's annual Budget is another function which Dr Tan does with the close involvement of the CPA.

Dr Tan and the CPA would meet Finance Ministry officials to hear the Government's spending priorities, and clarify questions they might have on the Budget.

This is because after the Budget is presented to Parliament and approved, it goes to the president, who will consult the CPA for their recommendation and decide whether to give his assent."The actual figures are fairly straightforward. What is less straightforward is understanding the motivation, the concerns of the Government and the issues they see ahead," Dr Tan says. "Also, (understanding) the implications of some of these expenditures, because they may take many terms of government."

To better understand the workings of major agencies, Dr Tan says he and CPA members have made visits to the Housing Board and JTC Corporation, as well as newer towns like Punggol to see developments first-hand and what the Government is doing to improve the lives of Singaporeans and benefit the economy. "You talk to people who are actually doing the job, and see what they are concerned with on a day-to-day basis rather than just at the policy level," he says.

Asked for his assessment of his term in office, he says: "I've done my best. It's been hard work but it's always been very rewarding. How Singaporeans will regard me, that's for Singaporeans to decide.

"It's been an honour and a privilege to serve as your president. I'm glad to have been able to help Singapore continue to progress."

In carrying out his duties during the six years in office, Dr Tan has also been steadfastly supported by his wife Mary, 76, who is often by his side at community events.The quiet ways of Mrs Tan, who is also warm and friendly, have endeared her to many, say Istana staff, officials and ordinary Singaporeans who visit the Istana when it is open to the public.

Dr Tan seems more approachable when his wife is with him. "She has a way of empathising with people, and they warm up to her," he says.

Has she softened his image?

"I won't say soften. I don't think I've got a harsh image," he says with a chuckle. "We each contribute in our own way."