In 2003, Mr Harbhajan Singh was 63 and on a yearly re-employment contract after having worked in Tan Tock Seng Hospital (TTSH) for almost 40 years.

Little did he know that he would soon need to tap skills and experience garnered from a lifetime of nursing work to meet the biggest challenge of his life: fighting a national crisis on the front line.

In March 2003, the severe acute respiratory syndrome (Sars) hit Singapore, and the Communicable Disease Centre (CDC) became the main battlefield.

Mr Singh, then a unit nurse manager with more than 100 nurses under his charge, recalled receiving a phone call from the Ministry of Health telling him to get the CDC ready to receive Sars patients.

He knew he had a problem.

The CDC did not have many individual isolation rooms with built-in toilets, and the single rooms were occupied by HIV (human immunodeficiency virus) patients.

He moved the HIV patients elsewhere within the CDC and arranged for the discharge of patients with skin conditions to make space for the incoming suspected Sars patients.

Things were only starting to get stressful. Family members of suspected Sars patients were unhappy as they were initially not allowed to visit their loved ones. Donations of food and other items streamed in but they were all left outside the CDC as the delivery people did not dare to enter.

In the first few days that they started housing Sars patients, one of the patients absconded. Mr Singh had to alert the authorities and quick action had to be taken.

It was only about two weeks later that TTSH became the designated hospital for Sars and took some of the load off the CDC.

"It was the toughest two weeks of my life," said Mr Singh, 78.

"We were battling an unknown enemy and I could not risk infection and endanger my family, but I wanted to help alongside my team as much as possible," said Mr Singh, who has four children and four grandchildren.

Five healthcare workers here died from Sars after coming into contact with patients. Two of them were his colleagues.

Mr Singh received a National Day Award that year for helping Singapore in its battle against Sars.

In 2015, TTSH gave him the title of "Emeritus Fellow", an award normally given to doctors. Mr Singh, who is still working part-time at the hospital, is the only nurse to have received the award from the hospital so far.

"As long as I can still contribute, I will keep working here," he said. "There is a kampung spirit here and 11 Jalan Tan Tock Seng has become like my home address."