The first mourner to pay her respects to the Queen at Westminster Hall said the experience has helped her cope with the death of her husband.
Ms Nanthakumaran, 56, who spoke to the PA news agency when she reached Lambeth Bridge at noon on Monday, said her husband Nallathamby Nanthakumaran died in February.
I'm so privileged that this opportunity was given to the public. I will be remembering this for my life
She was in the middle of preparing food for loved ones for a seven-month memorial when the news of the Queen’s death broke on September 8.
Speaking to PA on Thursday after she had paid her respects to the Queen, Ms Nanthakumaran said: “I lost my husband in February and (seeing the Queen’s coffin) helped me overcome the bereavement.
“It is helping me in the process of my husband’s death – it was just sharing this that is helping me as well.”
Ms Nanthakumaran said queuing for two days and being interviewed by the media was a “different experience”.
She said she was “happy” to be the first to see the Queen and be “involved in a bit of history”.
“I’m so privileged that this opportunity was given to the public,” she said.
“I will be remembering this for my life.
“I still can’t believe it – it’s unreal that I have done it.”
She spent the two days with Anne Daley, 65, from Cardiff, and Grace Gothard, from south London – the second and third people to join the queue – and they took turns to have naps in a shared sleeping bag.
“Everyone was friendly,” Ms Nanthakumaran said, adding that volunteers, police and stewards brought them food, coffee and even a gazebo to shelter under.
Ms Nanthakumaran said Monday night was “OK” and “warm” but Tuesday night “was the challenging one as it was raining hard”.
“Even though it was rain or shine, it was worth the wait that we made it for our special Queen. It is once in a lifetime – we aren’t going to see her again,” she said.
“I was determined to do this from the time I heard that the Queen had passed away.”
On walking into Westminster Hall, she said she was “really nervous” and felt the weight of being the first mourner.
“I was controlling my emotions when I was walking in there,” she said. “I didn’t want to emotionally walk in there, I wanted to do it properly.”
The atmosphere was “peaceful”, she said, adding: “I felt like I was the only person there.
“It was a sad experience and very emotional.”
Ms Nanthakumaran said she curtsied, said prayers in her head and thanked the Queen for “her great service”.
“It was only when I went past, it then hit me that she has really gone, that it’s real and it’s no more, and we are never going to see the Queen again,” she said.