Financier Ben Goldsmith and banking heiress Kate Rothschild are said to be "united in grief" following the death of their 15-year-old daughter in a "quad bike accident".
Iris Annabel Goldsmith, one of three children of Mr Goldsmith and his former wife Ms Rothschild, died at their family farm in the village of North Brewham, Somerset on Monday, according to reports.
The teenager is the niece of Tory MP Zac Goldsmith and documentary producer Jemima Khan, the former wife of Pakistan Prime Minister Imran Khan.
Police and ambulance crews were called to the address at around 3.15pm, and a report into the death – which is not being treated as suspicious – is being prepared for the coroner.
South Western Ambulance Service said it was called to attend an incident involving a vehicle – described by The Times as a cross between a quad bike and a Jeep – and sent an air ambulance, a critical care team, a land ambulance and two other paramedics to the scene.
One neighbour said the death of the 15-year-old – who had reportedly been riding the vehicle with a friend – had left the small community devastated.
He told the Daily Mail the whole village has been affected by the tragedy, which a family friend said had left the two parents numbed to their core.
Iris was a complete firecracker – an absolute delight, they told the newspaper.
Everyone in the family loved her to bits. She was beautiful, charming, intelligent, wonderful company and absolutely the loveliest person you could meet.
Ben and Kate are completely devastated. They are numbed to their core and united in their grief. Iris captured the charm of Ben and the sense of Bohemian charisma of Kate. All the family are rallying round Ben and Kate.
The former couple – who have two sons, Frank, 13, and Isaac, 11 – are worth hundreds of millions of pounds and hail from two of the most powerful families in the UK.
Mr Goldsmith is an adviser to Environment Secretary Michael Gove and is chairman of the JMG Foundation, which provides funding for eco-friendly campaigns.
Ms Rothschild – who split from Mr Goldsmith in 2012 after nine years of marriage – is the heiress to the Rothschild banking empire, owned by one of the wealthiest families in the world.
Avon and Somerset Police have said the entire family of Iris have requested privacy during this difficult time.
In a statement, the force said: We were called at about 3.15pm on Monday, 8 July to a farm in the North Brewham area following the sudden death of a teenage girl.
The girl’s death is not being treated as suspicious and officers are now carrying out enquiries on behalf of the coroner.
The family ask the media to respect their privacy during this difficult time.