DAVID and Samantha Cameron always knew their little boy Ivan's life would be cut tragically short because of his disability.
But the Conservative leader and his wife were yesterday left reeling with grief by the sudden death of their elder son.
When he held his shadow cabinet meeting on Tuesday evening, Mr Cameron had no inkling of the heartbreaking events that would start to unfold that night.
He was planning a dinner of pancakes at home for Shrove Tuesday with his wife and their three children – Ivan, Nancy and Arthur.
Aides described Mr Cameron as being in "good spirits" throughout the day on Tuesday.
Just a few hours later, his tragedy would unite the political establishment and the country in grief.
Six-year-old Ivan, whose life had already been blighted by his neurological disorder, Ohtara, a severe form of cerebral palsy which comes with bouts of epilepsy, took a turn for the worse.
A quadriplegic, Ivan had not been able to crawl, walk or talk properly.
The family had been braced that he would not survive into adulthood and a health scare last year forced the Tory leader to postpone a trip.
But as William Hague, the shadow foreign secretary, said, the boy's long-term illness did not make his passing less tragic.
The Camerons had access to round-the-clock care to help with their eldest child and had resigned themselves to regular dashes to the hospital.
But early on Wednesday, Mr Cameron knew things were very serious.
"When they took him to hospital it became apparent that he wouldn't make it," a party spokesman said.
"They had no particular warning. Ivan had a bad night, but he's had bad nights before. They got him to hospital, but he did not pull through."
The spokesman said the mood in Conservative headquarters was very sombre, not least because the close-knit team had regularly met Ivan. His premature death came as a shock.
The Camerons took Ivan to the hospital early yesterday, before 6am, and he died 45 minutes later after a severe seizure.
The cause of death was acute abdominal failure.
Yesterday evening, Mr Cameron, his wife and their two children were at home in their west London terraced house. It had been adapted for Ivan's wheelchair, which Mr Cameron collected from the family's people carrier yesterday.
The Camerons asked for privacy to let them grieve.
Sources close to the Camerons made clear that the Tory leader was very grateful for the outpouring of public support. But a friend said he realised he was not the only parent living with such tragic events.
The Tory leader is not expected to be back at work for at least a fortnight.
As news broke of the tragedy, tributes flowed from around the country. The Queen sent a personal message of condolence.
Some members of the shadow cabinet, who were holding an unofficial meeting, did not know about the tragedy yesterday morning.
But from about 8am, Mr Hague knew about the death and was fully prepared to speak on behalf of the Tories for Prime Minister's Questions.
Then came the call from Downing Street: Gordon Brown suggested cancelling the weekly half-hour verbal joust and proposed party leaders issue tributes to Ivan instead. Tory sources said the gesture was "greatly appreciated".
Mr Brown suffered his own bereavement when his daughter, Jennifer Jane, died at just ten days old in 2002.
A visibly moved Mr Brown told a subdued House of Commons: "I know that the whole House will want to express our sorrow at the sad death this morning of Ivan Cameron at the age of just six years old.
"I know that in an all too brief life, he brought joy to all those around him and I know also that for all the days of his life, he was surrounded by his family's love.
"Politics can sometimes divide us. But there is a common human bond that unites us in sympathy and compassion at times of trial and in support for each other at times of grief. Sarah and I have sent our condolences to David and Samantha and I know the whole country – our thoughts and our prayers – are with David, Samantha and their family today."
Vince Cable, the Liberal Democrats' deputy leader, said there was something "especially sad and shocking about the loss of a child".
George Osborne, the shadow chancellor and a close friend of Mr Cameron, said Ivan's death had been sudden. "It has left the Cameron family in a great deal of grief and shock," he said.
Mr Cameron often had to break engagements to join his wife and son in hospital and he often spoke of his gratitude to the NHS for its care.
He spoke in detail about Ivan's illness on BBC Radio 4's Desert Island Discs in 2006.
He compared finding out his son was disabled to being hit by a freight train. It was "almost like mourning the loss of something, because you are mourning the gap between your expectation and what has happened".
After struggling to come to terms with the situation, he spoke of one moment driving home from hospital where he believed the family would get through it and not fail Ivan.
"He is a wonderful boy. He has got the most lovely eyes and he definitely interacts with us in the way he looks at you and the way he moves his head, but he often is in a lot of pain," he said.
Mr Hague yesterday perhaps best summarised the mood for those who knew Ivan.
"Ivan their son suffered much in his short life but he brought joy and love to those around him. As David has said, for him and Samantha he will always be their beautiful boy."
Day nurse told me my baby could be dead within a week
ON 18 JANUARY, 2002, I became a mother – a moment that should have been the most joyous and exhilarating experience of my life. But as my baby girl was whisked away to the intensive care unit, I became overwhelmed by a feeling of utter panic and despair.
Within minutes of the birth, I was taken to one side by a grim-faced midwife, who warned me not to become too attached to my little girl, as she may not survive the week.
I didn't resent her harsh analysis of the situation. I was glad of it. I couldn't bear the thought of bonding with Helena over a period of days or weeks, only to find I had lost her. And no amount of reassuring words or logical thought from my husband put my mind at rest.
Weighing just 2lb 11oz, she was taken from my arms and placed in an incubator. There she was hooked up to a heart monitor and breathed with the aid of a ventilator. We were told by the doctors not to plan too far ahead. Death, brain injuries, blindness, learning difficulties – all were possible outcomes for a baby born so prematurely.
Then there was the parents' room at Simpson's – a dreadful place where doctors broke the devastating news to those parents whose babies were not going to survive. And never far from my mind was the thought of Gordon and Sarah Brown, whose premature baby, Jennifer Jane, had died just 20 days earlier in the same neo-natal unit.
We were lucky. Helena was discharged after eight weeks with no ill effects.
Now, as the parent of two healthy little girls, I can only imagine the sense of grief David and Samantha Cameron feel on the death of Ivan. Anyone who has ever nursed a sick child and feared the worst will sympathise with their plight.
As most children with his condition die within the first two years of life, the Camerons may well have spent years anticipating his death. But no amount of planning could prepare a parent for that moment.
Friends who have lost children, especially at such a young age, say they never truly recover from it. As the years pass, every missed birthday and Christmas holiday is a stark reminder of what they have lost.
'You can't take a break'
MY WONDERFUL son, Kier, was diagnosed with cerebral palsy when he was six months old, writes Martin McArthur.
It was a life-changing experience, and while I knew I couldn't wave a magic wand and get rid of my son's disability, I desperately wanted to make it better.
The common message I received at that time was: get your boy into Bobath therapy. It's a holistic, trans-disciplinary approach provided by a Scottish charity, involving occupational therapy, physiotherapy, and speech and language therapy. So that's what I did. With every visit to the Bobath Children's Therapy Centre in Glasgow from the age of two, Kier's condition improved. The charity's therapists taught me how to help him at home with daily exercises.
Now 11, Kier's mobility is restricted and he relies on a walking frame and, on occasion, a wheelchair. But he's as sharp as a tack. He's been through a bit of a tough time recently – his hamstrings haven't caught up with his growth spurt, which has placed enormous pressure on his knees, leaving him in a crouched position.
As a parent, you can't take a holiday from cerebral palsy. Every day has to be planned like a military campaign.
If you work at it, the rewards are great because you can make an improvement and help your child realise their full potential.
• Martin McArthur is chairman of Bobath Scotland, a therapy centre that looks after children with cerebral palsy
Grief is as different as your fingerprints
ONE of our volunteers once told me that every person's grief is as individual as their fingerprint and, certainly, we see in our work that different people grieve in very different ways.
For most people, grief can be a very painful experience. I would not say one kind of loss is harder to bear than another, but we certainly see in our work that the loss of a child is a particularly tough one.
I also think it is often very tough if there are other children in the family. Depending on the age of the children, it can be difficult for them to understand the permanency of the loss.
To help a child, it's best to try to answer their questions honestly – and for a parent (who will often be the best person to answer those questions), that can be really hard to do as they struggle with their own grief.
It is difficult, indeed impossible, to imagine how David Cameron and his family are feeling. His two other children are still very young and, in addition to coping with their own grief, he and his wife will want to do their very best for them.
In terms of the parents, no two people grieve the same way.
It is important that we now give the Camerons time and space – and privacy to do their grieving.
• Stewart Wilson is the chief executive of Cruse Bereavement Care Scotland.
IVAN Cameron suffered from cerebral palsy as well as Ohtahara syndrome, a rare form of epilepsy, where babies start having seizures in the womb or the first ten days of life.
Some babies suffer up to 100 seizures a day. The condition is thought to affect about 0.2 per cent of UK children with epilepsy, with a slightly higher occurrence among boys.
The condition is believed to be caused by an underlying structural brain abnormality, which may have been passed on through the parents' genes, or caused by brain damage at birth. Babies with Ohtahara syndrome are often floppy and excessively sleepy, going on to develop stiffness, or spasticity, in their arms and legs.
David Cameron and his wife, Samantha, realised Ivan was making sudden jerky movements within days of his birth in 2002. Affected babies remain dependent and do not feed well. It is not uncommon for infants to die before they reach the age of two, because of repeated chest infections.
Ivan's condition required round-the-clock care, with up to 26 medications a day.