SINGAPORE -When Dr Tony Tan stepped forward in 2011 to stand in the presidential election, he knew public sentiment was still roiling from the intense contest of the General Election a couple of months earlier.

His long association with the Government would affect his chances, yet he chose to run in the electoral race as he felt the country needed a steady and experienced person who understood the role of the President and would stay above the political fray, noted Prime Minister Lee Hsien Loong on Thursday (Aug 31).

"Fortunately, you were elected, and Singapore has benefited greatly from your calm and dignified presence, wealth of knowledge and steady judgment," said Mr Lee as he recounted Dr Tan's challenging start as Singapore's seventh president.

The President, as the Head of State, sits at the apex of the political system and the country, and Dr Tan has worked tirelessly to fulfil the important responsibilities, he added.

"Domestically, he has to be a unifying figure to all citizens. Externally, he represents Singapore to other nations. He is also the custodian of our reserves and of the integrity of the public service," Mr Lee said.

He was speaking at a farewell reception for the President at the Istana that was attended by more than 200 guests, including Cabinet ministers and MPs.

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The Prime Minister, in his speech, cited the many milestones in the President's six-year term.

Dr Tan expanded the President's Challenge drive to include volunteerism and social entrepreneurship and supported community efforts to promote harmony between racial and religious groups.

He gave recognition to the work of nurses and teachers, supported national athletes and local artists, and helped Singaporeans better understand the Istana and the Presidency by starting the Istana Heritage Gallery.

During the SG50 celebrations, he hosted many commemorative events, both in Singapore and abroad, to deepen Singaporeans' sense of unity and attachment to the country and to show appreciation to the pioneer generation.

Internationally, Dr Tan also widened Singapore's circle of friends through many top-level exchanges with foreign leaders.

Dr Tan made more than 30 state and official visits, including to countries no Singapore president had visited before. And he would take business delegations with him to open doors for Singapore companies.

"Your visits were also occasions to promote cultural, scientific and technological collaborations, fields in which you had a special interest," Mr Lee said, adding: Your efforts have strengthened ties with our friends and highlighted opportunities to do more together."

As a custodian of the national reserves, the President was "prudent and conscientious", the Prime Minister said.

PM Lee giving his speech during the farewell ceremony for President Tony Tan

He ensured the reserves continue to be used only for good cause and that only well-qualified, suitable people are appointed to key public offices, Mr Lee added.

"We were able to operate these Presidential safeguards effectively and smoothly, because your office and the Government have had a close and constructive working relationship, based on mutual trust and respect," he said.

"We met regularly, often over lunch. I would update you on significant developments and plans. We would discuss impending appointments, the financial outlook and many other matters beyond the President's custodial responsibilities.

"These informal interactions helped us to understand each other's thinking, and enabled the formal mechanisms of the elected Presidency to function properly."

In response, Dr Tan thanked Mr Lee and said he was glad the Prime Minister and his colleagues in the government could tap on his experience as a resource.

He said he greatly valued his regular meetings with Mr Lee, and noted that both their constitutional roles are underpinned by mutual trust and respect.

Looking back on his term, Dr Tan said he was determined that the Presidency should symbolise and champion the role that everyone can play to make Singapore a better society.

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That is why he encouraged citizens to give their time, talent and resources to help those in need, he said.

He spoke of the importance of building up the nation's "social reserves", a term he uses to describe the ties that bind people together.

Like financial reserves, social reserves are vital in uncertain times, he noted.

"Our progress as a nation is measured not only by our ranking on international tables or the success of our highest flyers. The measure of our society rests on how we care for those less fortunate than ourselves," he said.

As the nation's "chief diplomat", the state visits and overseas trips the President makes are important for raising Singapore's profile and maintaining strong relations with partners overseas, he added.

He was glad to meet Singaporeans on his trips, and said each of them is an ambassador for the country in their own way.

Mr Lee said he enjoyed working with Dr Tan, who was his first boss when he entered politics more than 30 years ago. Dr Tan was then-Minister of Trade and Industry.

"You mentored and guided me, and helped me to find my footing in government," Mr Lee said.

"Later, we were for many years Cabinet colleagues, working together in various roles. Like many others, I have always admired your clarity of focus, imperturbable demeanour and sense of duty."

"It was the same these last six years that you have been President. I am grateful that we have had a long, productive and happy working relationship, and hope that you will look back on it as warmly as I do," Mr Lee added.

"On behalf of the Government, my Cabinet colleagues, and all Singaporeans, I thank you once again for your dedication and distinguished service to the nation."

Dr Tan said the SG50 golden jubilee was the highlight of his term, as it provided a reminder of the passion and determination that brought the nation success.

Although founding Prime Minister Lee Kuan Yew's passing in 2015 tempered the joy of celebrations, he said it also revealed the depth of the relationships of Singaporeans, who came together to pay their respects to Mr Lee.

"We are now stewards of the legacy that he left us - the values of meritocracy, honesty and integrity. These will serve us well as we look forward to our next half century," he said.

Dr Tan, a former Deputy Prime Minister and Minister for Defence, said he and his wife Mary wish Mr Lee wisdom and good health in leading Singapore to even better days ahead.

"My time as President has been the highlight of my career. Personally, it has been a deeply moving opportunity to see a Singapore in all its diversity and to meet Singaporeans from all walks of life," said Dr Tan.

"Thank you, my fellow citizens, for giving me the opportunity to serve as the President of Singapore. It has indeed been an honour and a privilege," he added, stepping off the podium to a warm hug from Mrs Tan.

Earlier in the afternoon, about 50 staff from the President's Office lined the main corridor of the Istana Main Building to bid farewell to Dr Tan.

They were from the ceremonial and protocol, corporate services, statutory compliance, household, media and communications and Istana programmes departments and divisions.

From Friday, Council of Presidential Advisers chairman J. Y. Pillay will be Acting President until a new President is elected next month.