Tim Loughton is MP for East Worthing and Shoreham and a former Minister for Children and Families.

It was back in November 2012 that I published an open letter to the Prime Minister on this website requesting that he set up an overarching inquiry into historic child sex abuse in the wake of the flood of abuse stories coming out of the Jimmy Savile revelations.

Twenty months on, that flood had become a tsunami, engulfing the BBC, NHS, independent schools, churches, care homes – and it was threatening to cascade into the world of politics too.

Last month, together with Zac Goldsmith and five other MPs from other parties I wrote to the Home Secretary repeating that request, given the mounting pressure built up from the relentless headlines about yet another child abuse scandal. The campaigning website Exaro helped to spark a social media campaign, putting the matter on MPs’ radar – and after I wrote to all colleagues last week inviting them to co-sign our letter no fewer than 141 had done so by Monday, and rising.

Theresa May is to be greatly commended for grasping the nettle, and at last announcing just such an inquiry on Monday. The tide had become irresistible. Stories about missing files abounded. Conspiracy theorists went into over-drive. Public confidence in our child protection system and the ability of public agencies to get to grips with the confusing array of abuse stories was becoming seriously undermined. The media and at least 141 MPs could not, -and were not going to let it go.

Theresa, almost uniquely amongst Cabinet colleagues, seems to have appreciated the gravity of what has been going on, and the need for transparency and urgency in investigating it fully. It does not help that just 24 hours earlier other cabinet colleagues were still trotting out the discredited mantra that we didn’t need an overarching inquiry. Disgracefully, political has-beens such as David Mellor wheeled themselves out to trash the whole story on the basis that Geoffrey Dickens was never going to win Mastermind, and people who had not seen the Dickens dossier should not comment on it. For good measure he had not himself seen it, he commented.

The Government could and should have been on the right side of this argument for an enquiry earlier. It had become inevitable, and there was no discernible downside in resisting it. I still don’t understand why they weren’t. Clearly, it hasn’t helped that responsibility for children and young people’s issues has now been fragmented from the deafeningly silent DfE across Government departments.

Whilst Education retains its interest in children in care and supposedly child protection, child sexual exploitation has now gone to the Home Office; regulating child access to online sexual images has gone to DCMS; DCLG is responsible for the troubled families programme, youth justice and the family courts is now looked after by the Department for Justice and youth policy has been ejected to the Cabinet Office.

Ironically and more frustratingly, this Government has done more than any previous one in overhauling the way we do child protection in order to make our children safer. The Child Sexual Exploitation Action Plan we launched in 2011 has meant many more recent victims coming forward, being taken seriously by police and social services – and the perpetrators being relentlessly pursued through court and into jail.

But even the most hardened child protection professional must have been aghast at the latest revelations of the activities of serial abuser, Jimmy Savile. 28 reviews have been published so far, with at least seven more to come on Savile’s wickedness in the NHS alone. That is aside from what he got up to in care homes, schools and the BBC, with over 500 victims bravely coming forward to date. Then another previously cherished doyen of children’s TV is sent down for historic sexual abuse whilst new revelations about the murky paedophilic predilections of that colossus of Liberal politics, Cyril Smith, hit our television screens.

That is just the last week’s update on Child Abuse UK. And those of course are the high profile cases which hit the headlines whilst we know that the vast majority of ‘mainstream’ sexual abuse and child cruelty happens at the hands of nonentities who operate computers, drive taxis, run kebab shops or teach or treat our kids.

Almost two years on from the extraordinary revelations about Jimmy Savile, child abuse has never had a higher profile. That is perhaps the only compensation from this vile episode for a vile practice which has often previously gone largely untouched by the media. But at the same time, parents have never been in greater need of reassurance that the problem is being effectively dealt with.

The most recent allegations which cast their tentacles to the world of politics raised serious question marks about who was covering up for whom, and why the police and justice system failed to pursue the alleged offenders more robustly. At best it was the dangerous complacency of an age and attitude that said ‘Oh, that’s just Jimmy.’ At its worst, it was complicity to turn a blind eye or actively confound action to investigate shocking acts of child rape and systematic abuse for gratuitous pleasure leaving the victims to suffer the trauma for decades, compounded by a failure for anyone to take them seriously.

All of this makes the announcement of the inquiry so important. It will not be an easy inquiry to run. It will take time and the gravitas of the people running it and its terms of reference will be key. The appointment of the redoubtable Elizabeth Butler-Sloss as its Chair is a solid start. Crucially, Theresa has said that full transparency will be at its heart and that if it finds that its activities are being hampered then it will be flexible enough to be transformed into a full blown public inquiry with all the additional teeth that brings. But basing it on the Hillsborough Independent Inquiry panel model, which worked so well and led directly to the new inquests currently underway, is a sensible way to go.

It needs to put into chronological context the whole sordid history of child abuse in this country going back to the 1960s. It must be a commission of respected figures from the law, lawmakers, social services and children’s charities. It must set out to provide the holistic reassurance that has been so sapped by the plethora of past and ongoing inquiries and reviews, and it must leave no stone unturned.

Such an inquiry must address four main issues.

What exactly happened and why, over all those years?

When did things start getting better, and how?

Have all practical steps been taken to give victims the confidence to come forward and for the police to pursue vigorously any remaining offenders, and that should include anyone implicated in covering up or wilfully failing to pursue allegations?

And perhaps most importantly of all, have all our major institutions that have significant dealings with children and young people instituted child protection policies and practices that are fit for purpose in 2014 to deal with modern technology and savvy perpetrators and are they being followed?

Given his own deep interest in combating the cancer of child abuse, I hope the Prime Minister will make it his personal mission to make sure this inquiry leads to something and nothing impedes its progress. Only when we really appreciate the depth of the problem and the breadth of what is being done to tackle it can we all as a nation take on board that we all have a duty to be vigilant to protect of our most vulnerable children from those who would do them harm.