What’s the price of political stability? Over the past week, long-standing rumours that senior members of the political establishment abused children in the 1980s have finally been broadcast in the public domain, and the Home Secretary, Theresa May, has announced an inquiry. “Frightened survivors of child abuse deserve the truth,” said Tom Watson, a Labour MP who has spoken up for those survivors, addressing the House of Commons.

So do the rest of us. If it is true that, at the highest levels of Westminster, the abuse of young people has been covered up by those who might have helped the victims see justice, it will go beyond scandal and will demand a response beyond outrage. It will demand that we examine, as a nation, what has become of our political culture and who it exists to protect.

It is already beyond question that powerful politicians such as the late Cyril Smith MP and well-connected celebrities such as Rolf Harris and Jimmy Savile – who was close to the royal family and to Margaret Thatcher, lunching with the then prime minister at Chequers – were allowed to abuse young people with impunity for decades. It is plain fact that Smith raped young boys in establishments to which he had access, including the Knowl View special school in Rochdale. Efforts by staff members to bring the matter to police attention were repeatedly frustrated.

It is known, too, that Savile, Harris and other once-respected public figures preyed on children for many years and that their victims were too frightened to come forward until recently. It is becoming clear that the rape and abuse of boys and girls was a tacit privilege of the elite in the Heath, Wilson, Callaghan and Thatcher years, enabled by the silence of those invested in their success and those intimidated by their power.

The question now is not whether it happened, but how much of it went on. The question is who knew about it, and who helped to ensure that survivors were not

believed, that evidence was suppressed. The question is: if abandoning children to rape, violence and abuse is the price of preserving public faith in the establishment, what sort of establishment have we got, and what is our faith worth?

It is also known that in 1983, a batch of files pertaining to child sex abuse at the highest levels of state, now known as the Dickens dossier, was handed to Leon Brittan, then home secretary. That dossier has gone missing, along with 114 other relevant files, shown to various home secretaries. I have been told that other papers may have been removed from files that are still available.

Where is that dossier? Where are those 114 missing files? And, most importantly, how can a state that prides itself on operating one of the most efficient and invasive surveillance networks in the world manage to lose seemingly every scrap of evidence that might have implicated its own leaders in sex crimes against children?

I spoke to a politician close to the case. It was confirmed to me that allegations of child abuse by Cyril Smith and many others had circulated for decades. With every such story, more of the same pattern emerges: public-sector and care workers bring their concerns to the authorities and they are ignored or turned away. Evidence goes missing. Cases are brought forward but then dropped by prosecutors without explanation. Frightened child victims grow up into traumatised adults. Peter Hatton-Bornshin, abused at the Grafton Close Children’s Home in Richmond, which has been linked to the current inquiry, took his own life in 1994 at the age of 28.

The long list of abuses and obfuscation is part of a mosaic of corruption that has been exposed over the past half-decade, brushstroke by brushstroke, lying under the solid floor of the Palace of Westminster.

The broader pattern takes in the MPs’ expenses scandal of 2009 to 2011 as well as the Leveson inquiry into phone-hacking and other press abuses by the Murdoch media group. As decades of dust and selective amnesia are scraped away, a picture begins to emerge. It is one of a political culture that accepts corruption and abuse as the price of stability. It is a picture of a political culture that would rather harbour criminals than hold itself to account.

What happened at Grafton Close? What happened at the nearby Elm guest house in Barnes, south-west London, that notorious “boy brothel” patronised by diplomats and spies? Most of all, what makes a person feel that his power entitles him to abuse children, to assault young girls and boys, not just

with impunity, but with the luxury of access to the very institutions designed to protect the vulnerable – hospitals, care homes, orphanages? What kind of culture harbours politicians who believe the privilege of office extends to privilege over the bodies of the young, poor and powerless?

The public deserves the answers to all of these questions – not out of lewd fascination, but because if a political class cannot and will not hold itself to account, then its mandate to rule disintegrates. If justice is to be served, there must be a full public inquiry, similar to those overseen by Lord Hutton and Lord Justice Leveson. We deserve to know what was done by members of the establishment of the 1980s that created the society in which we live today, just as the victims of historic abuse deserve justice.

Unfortunately, a full inquiry would bring headlines associating the Conservative Party – on whose watch, in the 1980s, all of these allegations first came to light – with paedophilia and subterfuge in an election year. Is the integrity of the establishment worth that much? The answer will determine what sort of nation we are, and what sort of nation we wish to become.