This was a typical night in our house, and it was followed by a typical day of attempting to balance work and family while caring for a severely disabled child and engaged in a ceaseless battle against the bureaucracy of our public services. My wife endures a daily torrent of telephone calls and conversations with doctors, nurses, social workers, teachers and therapists, plus the whole allied panoply of respite carers and council staff.
This is the reality of life as the parent of a severely disabled child. It is a reality I entered 12 years ago with the birth of a child suffering complex epilepsy that has left her blind, unable to walk or talk and in need of 24-hour care. It has had an impact on my family, my friendships, my lifestyle - and on my politics. My perceptions have been challenged, my views changed.
It is a reality that David Cameron, the favourite for the Tory leadership, entered nearly four years ago with the birth of his son Ivan. As I know from a series of conversations with him since then, it has had a similarly profound impact on his life and his politics. It helps explain his evolution from that young Thatcherite turk who stood in the shadow of Norman Lamont on Black Wednesday to a more complex, compassionate figure.
To understand the man who many believe could rejuvenate his floundering party, it is vital to appreciate the impact of this trauma. He may be comparatively untested politically, but he has survived a huge personal test which, given what takes place behind his front door, puts the daily ups and downs of politics in proper perspective. Those that dismiss him as a toff who has risen without trace may be making a mistake; for once, the personal is deeply political.
We have both been thrust, unwillingly at first, into the world of the disabled, a land shamefully ignored by the rest of society. We have come to learn, from bitter personal experience, the human consequences of the scandalous closure of special schools. We have had far too much first-hand experience of the shocking state of our National Health Service. We have seen the failings of our social services and the paucity of respite provision offered to carers. We have felt the helplessness when confronted by uncaring local bureaucrats who hold the keys to a better life for our families - and the immense gratitude for those who appreciate our travails. And we have come across the human cost of these failures by the state in destroyed families, mental health problems and alcoholism.
This was not the world I envisaged that I would live in. Six weeks after the birth of our second child, and four days before Christmas, a paediatrician was informing us that our daughter was "profoundly brain-damaged". There was depression, grief for the child we thought we had and, slowly in my case, the gradual emergence of joy in the beautiful child we are fortunate to have - a process Mr Cameron has spoken movingly about.
Until my daughter's birth, I shared the consensus that the NHS was a source of national pride. Not for long. I have seen too much incompetence, too many horror stories. Some were serious: the internationally-renowned neurologist who measured our heads before declaring that my daughter - then suffering up to 30 fits a day - would just have a slightly lower IQ than normal; the GP who gave my daughter an injection despite a warning on her notes that it could prove fatal; the two-day struggle in A&E to get a vital brain scan carried out after she fractured her skull.
Then there are those smaller, but still significant, issues: the overcrowded waiting rooms, the dirty wards, the lack of anyone in charge, the patronising attitudes of some doctors, the nurses who ignore your child.
I was quickly convinced that part of the problem was the lack of patient power in the face of a monopolistic service. Five years ago, even William Hague dismissed my views on the need to break up the NHS as ludicrously right-wing. Today, the more astute politicians in all three parties - including, increasingly, the Prime Minister - understand the scale of the problem and the need to empower patients.
Mr Cameron, too, has seen his child suffer needlessly. And I know that he has reshaped his views during those long, lonely nights in emergency wards. He remains, though, a "Fabian", as one of his closest colleagues put it, believing in gradual change rather than the more drastic approach I would favour.
This is just one example. There are so many others. Mr Cameron raised the issue of special schools after the threatened closure of a centre attended by his son. Having spent the past few months trying to find a new school, I have seen the cost of the obsession with inclusion that has seen nearly 100 of these centres of excellence closed under Tony Blair. Inclusion is a fine aim, but it has become an over-riding dogma at a time when there is a rise in the number of kids born with multiple disabilities.
Then there is social services. What good is it if your social worker seems to change once a year, as ours have on average, ground down and spat out from this Cinderella service. Why does there need to be so much infighting between government departments over funding, which leaves parents caught in the middle fighting to protect their child's corner? Why is respite provision - which can make the difference between keeping a family together and a child being thrown into care - so inadequate? And why do those people who devote their lives to helping the disabled have such lowly status and poor rewards?
Most of these issues have huge political dimensions, of course - and it is little wonder that while so many middle-class parents fight their way through the system, so many less fortunate families fall apart or end up with inadequate care. Special needs provision is very expensive - we have recently spent £100,000 adapting our house, for example, while our daughter's education costs taxpayers more than that each year - but, as with the health service, it is not just about money. I am sceptical, for example, about the current fad for "localism" after our experiences. Mr Cameron, meanwhile, feels passionate about the inadequacy of respite offered to carers and the jumble of bureaucracy and assessments facing parents.
These failures towards some of the most dependent people in society offer lessons for the whole nation. I may not share all of David Cameron's views, but I know he understands these lessons better than most of his Westminster colleagues. He has gained an unwanted but unique insight into how our public services can be reformed and our government made more responsive to the needs of its citizens. In the end, this is a far more profound part of his political DNA than his old school tie or his antics in the Bullingdon Club.
A longer version of this article appears in this week's edition of 'The Spectator'Reuse content