The former IT girl had been battling a brain tumour and she was discovered by a friend in her apartment shortly before 2pm.
Workmen in the flat below her penthouse said they had not seen Tara, 45, since they heard the loud crash from inside on Friday.
The builders said they heard an alarm around 1pm yesterday and moments later emergency services arrived.
Tara Palmer-Tomkinson was found dead yesterday in her London home
Tara Palmer-Tomkinson looked downcast in final photos before death
Tara Palmer-Tompkinson dead: Troubled socialite craved happiness
Builders said they heard a "very loud bang" five days before Tara was found dead
"We’d hear her walking around up there," a builder told The Sun.
"But last Friday we heard a very loud bang in the afternoon — like someone or something falling over. We hadn’t seen her or heard her since then."
Police said Tara’s death is being treated as “unexplained” but are currently not treating it as “suspicious”.
The former I’m A Celebrity… Get Me Out of Here! contestant revealed last November that she had been battling a brain tumour after doctors discovered it in January last year.
Tara Palmer-Tomkinson was famed for her tumultuous lifestyle
Tara Palmer-Tomkinson 1971-2017
Wed, February 8, 2017
Socialite Tara Palmer-Tomkinson, the original 90s 'It Girl' has died aged 45 after battling a brain tumour.
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At her birthday party in Mayfair in 1998.
The former IT girl had been battling a brain tumour
Opening up about the illness, Tara confessed: "I went to the doctor to talk about my latest blood test results when I got back from skiing in January.
"I said, 'What does it mean? Can you translate it?' And the doctor said, 'As I suspected, you have a brain tumour'.
Further tests showed the TV personality was also suffering from a rare auto-immune condition, related to her anti-neutrophil cytoplasmic antibodies (ANCA-related), meaning abnormal antibodies attack the body's cells and tissues.
The daughter of Prince Charles' close friends Charles and Patricia Palmer-Tomkinson, Tara was famed for her tumultuous lifestyle and her public struggle to battle her drug problem.
Tara Palmer-Tomkinson's god-father Prince Charles said he was "deeply saddened" by her death
Duncan James was close friends with Tara Palmer-Tomkinson
Prince Charles – Tara's god-father – led the tributes to the socialite and said he was "deeply saddened" by her death.
In a statement issued by Clarence House, their Royal Highnesses The Prince of Wales and The Duchess of Cornwall said: "We are deeply saddened and our thoughts are so much with the family."
One of her best friends, Blue’s Duncan James wrote on Twitter: “Heartbroken and numb I have lost one of my oldest and dearest friends. I'm going to miss ur laughter the most shmooey. Rip sweetheart.”
“RIP Tara Palmer Tomkinson, 45. A fun, feisty woman who battled many demons. Very sad news,” Good Morning Britain host Piers Morgan posted.