The Location Location Location presenter said the day after her mother Lady Fiona Hindlip lost her 26-year battle with breast cancer, she was placed in a wicker coffin, lifted on to the back of a tractor and driven up the garden where she was buried next to Benji, the family pony.
It was the way Lady Hindlip wanted to be buried when she died in January – a simple, discreet ceremony and surrounded by her closest family.
Speaking for the first time about her mum's death, Kirstie said she realised the 66-year-old was dying when Kirstie's sister Sofie discovered she had bought a coffin and hidden it in the attic.
Kirstie, 42, told The Times: "When my sister went to get the Christmas decorations she found it – which was a bit of a shock.
"There was always a lot of very dark humour in our house. When Mum was alive her grave was dug so it was all ready. She wanted to be near Benji, our old pony's grave.
"She managed not to die on anybody's birthday. She managed not to die when anyone was out of the country.
"It's like she died when everyone had time to deal with it. We buried her in the garden the next day.
"We lifted her into the wicker coffin and we put her on the trailer on the back of the tractor and drove her up the garden.
"It was very important for her that it was very small – no strangers were involved of any kind, we had to do absolutely everything. For mum, it was all to do with discretion and privacy."
Kirstie, the eldest of four children, was 17 when her mum discovered she had breast cancer.
Lady Hindlip had a mastectomy, lumpectomy, a hysterectomy, had her liver taken out, several rounds of radiotherapy and chemotherapy.
She died just a few months after Kirstie disclosed that her younger sister Sofie, also a TV presenter, had had a double mastectomy to lower the risk of developing breast cancer, which has afflicted the family's female relations for generations.
In The Times interview, Kirstie, who lives with partner Ben Andersen, 55, and their four children, said she wants to help raise the profile of Maggie's, 'a charity which does what mum once did'.
She added: "It gives advice and provides a place and a cup of tea for those who have been diagnosed with the disease."
She said that she would like a Maggie's centre attached to every cancer hospital in the country to give emotional support and advice.
Kirstie said: "A lot of times the family will give a party for when the treatment is finished, they want it all to be over, but it's never over.
"Its impact on relationships and on children is enormous. People can be very angry. All sorts of emotions come out."
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