This will be one of those columns that leaves the writer, and possibly the reader, wanting a shower. How could anyone with pretensions to compassion attack a man who has been through hell with a desperately disabled child, for his treatment of the disabled, without feeling dirty? On the other hand, how can anyone with an average share of humanity look on the Ultimate Cage Fight between George Osborne and Iain Duncan Smith without feeling baffled and enraged by the Prime Minister?

Cynically, you can admire David Cameron’s legerdemain. The art of conjuring, as the newly late Paul Daniels knew, is diverting the eye away from the action. Whether by chance or cunning, Cameron has achieved this. Ever since Friday’s shock resignation reminded him of the need to beware the IDS of March, most attention focuses on the former Works and Pensions Secretary’s motives and implications for the Chancellor’s leadership ambitions. Almost no one has dwelt on how Cameron sanctioned the sustained raid on disabled benefits which Duncan Smith cites, a little unconvincingly, as the sole catalyst for his flounce.

This reaction reminds us that Cameron’s political hero is Mr Tony Blair (“the master”) who was so adroit at using lightning rods to spare himself the heat. Until exposed by the invasion of Iraq, he protected his reputation by having others (Alastair Campbell, Peter Mandelson, Cherie, even Gordon Brown) take the heat generated by things for which only a Prime Minister should ultimately be accountable.

To some extent, all governments operate in this way. Whatever Harry Truman claimed to believe, any leader’s guiding tenet is that the buck stops somewhere else. But Blair enforced this more skilfully than most, and it permitted him to cling to the pretty straight kinda guy facade long after it should have been apparent that he was a rogue and a charlatan.

Cameron has emulated his role model by outsourcing domestic policy almost in its entirety to an overmighty Chancellor, allowing him to play the part of innocent bystander when he chooses. If a Budget enriches high earners and cosseted pensioners by further impoverishing the poor – well, it’s CEO Osborne’s job to write the Budget, isn’t it, and non-executive Chairman Dave’s merely to endorse it?

But where Blair’s enmity with Brown gave him genuine cover from Budget disasters, Cameron’s friendship with Osborne offers him none. These two really are in it together. And what precisely it is that they’re in, or certainly ought to be, is a quicksand quagmire of their own creation.

7 ways the Tories have ‘helped’ disabled people Show all 7 1 /7 7 ways the Tories have ‘helped’ disabled people 7 ways the Tories have ‘helped’ disabled people Closing Remploy factories The Work and Pensions Secretary called time on Britain’s system of Remploy factories, which provided subsidised and sheltered employment to disabled people. People employed at the factories protested against their closure and said they provided gainful work. “Is it a kindness to stick people in some factory where they are not doing any work at all? Just making cups of coffee?” Mr Duncan Smith said at the time, defending the decision. “I promise you this is better.” The Remploy organisation was privatised and sold to American workfare provider Maximus, with the majority of the organisation’s factories closed. The future of the remaining sites is unclear 7 ways the Tories have ‘helped’ disabled people Scrapping the Independent Living Fund The £320m Independent Living Fund was established in 1988 to give financial support to people with disabilities. It was scrapped on July 1 2015, with 18,000 often severely disabled people losing out by an average of £300 a week. The money was generally used to help pay for carers so people could live in communities rather than institutions. Councils will get a boost in funding to compensate but it will not cover the whole cost of the fund. This new cash also doesn’t have to be spent on the disabled 7 ways the Tories have ‘helped’ disabled people Cut payments for the disabled Access To Work scheme Iain Duncan Smith is bringing forward a policy that will reduce payments to some disabled people from a scheme designed to help them into work. The £108m scheme, which helps 35,540 people, will be capped on a per-used basis, potentially hitting those with the more serious disabilities who currently receive the most help. The single biggest users of the fund are people who have difficulty seeing and hearing. The cut will come in from October 2015. The charity Disability UK says the scheme actually makes the Government money because the people who gain access to work tend pay tax that more than covers its cost. The DWP does not describe the reduction as a “cut” and says it will be able to spread the money more thinly and cover more people 7 ways the Tories have ‘helped’ disabled people Cut Employment and Support Allowance The latest Budget included a £30 a week cut in disability benefits for some new claimants of Employment and Support Allowance (ESA). The Government says it is equalising the rate of disability benefits with Jobseekers Allowance because giving disabled people more help is a “perverse incentive”. The people affected by this cut are those assessed as having a limited capability for work but as being capable of some “work-related activity”. A group of prominent Catholics wrote to Mr Duncan Smith to say there was “no justification” for this cut. Mental health charity Mind, said the cut was “insulting and misguided” 7 ways the Tories have ‘helped’ disabled people Risk homelessness with a sharp increase disability benefit sanctions Official figures in the first quarter of 2014 found a huge increase in sanctions against people reliant on ESA sickness benefit. The 15,955 sanctions were handed out in that period compared to 3,574 in the same period the year before, 2013 – a 4.5 times increase. The homelessness charity Crisis warned at the time that the sharp rise in temporary benefit cuts was “cruel and can leave people utterly destitute – without money even for food and at severe risk of homelessness”. “It is difficult to see how they are meant to help people prepare for work,” Matt Downie, director of policy at the charity added 7 ways the Tories have ‘helped’ disabled people Sending sick people to work because of broken fitness to work tests In 2012 a government advisor appointed to review the Government’s Work Capability Assessment said the tests causing suffering by sending sick people back to work inappropriately. “There are certainly areas where it's still not working and I am sorry there are people going through a system which I think still needs improvement,” Professor Malcolm Harrington concluded. The tests are said to have improved since then, but as recently as this summer they are still coming in for criticism. In June the British Psychological Society said there was “now significant body of evidence that the WCA is failing to assess people’s fitness for work accurately and appropriately”. It called for a full overhaul of the way the tests are carried out. The WCA appeals system has also been fraught with controversy with a very high rate of overturns and delays lasting months and blamed for hardship 7 ways the Tories have ‘helped’ disabled people The bedroom tax The Government’s benefit cut for people who it says are “under-occupying” their homes disproportionately affects disabled people. Statistics released last year show that around two-thirds of those affected by the under-occupancy penalty, widely known as the ‘bedroom tax’, are disabled. There have been a number of high profile cases of disabled people being moved out of specially adapted homes by the policy. In one case publicised by the Sunday People last week, a 48 year old man with cerebral palsy was forced to bathe in a paddling pool after the tax moved him out of his home with a walk-in shower. The Government says it has provided councils with a discretionary fund to help reduce the policy’s impact on disabled people, but cases continue to arise

After six years as their useful idiot, prosecuting their jihad against the vulnerable in the heart-rendingly naive belief that he was freeing the needy from the shackles of dependency, Duncan Smith finally snapped. You cannot discount wounded pride as a contributory factor with such a brittle, petulant man. Anticipating the sack after the EU referendum may have played its part. But whatever cabal of reasons lay behind his resignation, and however absurd it sounded coming from the frontman for the bedroom tax, he said something so ringingly true that it cannot be tainted by suspicions about his true feelings. He described these proposals for disability cuts as immoral.

Immoral, while technically correct, doesn’t go far enough. This is transcendently disgusting. It induces a purity of rage that borders psychosis. The idea of sons of privilege blithely nudging horrendously difficult lives closer towards the impossible could tease out the teenage revolutionary in a 92-year-old duke. No one who supported such cuts – no one who failed to oppose them – has a right to think of themselves as a Christian.

Iain Duncan Smith's resignation - How it happened

Cameron not only regards himself as a Christian. He has experienced levels of stress, anxiety, exhaustion, agony, misery and grief, as the parent of a severely disabled child who died, that most of us could imagine in only the barest outline, if at all.

He was, by all accounts, a magnificent father to his son. In general, so far as one can tell, he is not a callous person. Yet somehow, he has sat back these past years and committed a terrible sin – charitably, one of omission – by failing to prevent the disabled being implicitly slandered as scroungers. He let them be stigmatised, leading to an unconscionable surge of verbal and physical assaults. He allowed their lives, and those of their carers, to be made bleaker for the loss of respite care. But why am I falling into that lightning rod trap of using the passive tense? This buck, if no other, stops with Cameron. It is he, as Prime Minister, who has made those lives bleaker.

How someone who went through what he did with his son could fail to defend those going through it now (and without the wealth that cushions families like his from such indignities as begging local authorities for heavily rationed incontinence supplies), I have no idea. But then this is not one for the pundit. This is a case for a team of psychoanalysts working round-the-clock shifts in Vienna.

Cameron tells us he was puzzled and “disappointed” (that modern synonym for “so furious I could cut out his liver and force-feed it to him”) by Duncan Smith’s resignation. Our Viennese friends might interpret this as blatant projection. If Cameron is not puzzled by his own disregard for the disabled, if he isn’t furious with himself for colluding in their victimisation, one day he may be.