David Cameron was a highly effective Prime Minister. Despite the obvious constraints of being in coalition with the Lib Dems for most of his time in office, those were radical years. We have great benefits from his legacy of bold reform. But one area of complete failure was to reduce the number of children in care by increasing the rate of adoption. This was not due to any indifference from Cameron. He spoke passionately. Michael Gove, as Education Secretary, had responsibility for the issue – for whom it was personal.

During Theresa May’s premiership, we saw the failure continue. She set out to tackle “burning injustices”. But this was a spectacular example that got missed.

Under Labour, in March 2010, there were 64,000 children in care – of “Looked After Children”. The Conservatives at the time regarded that as scandalously high. Quite right. But now the scandal is even worse with the total having risen to 75,000.

In political terms, the direct impact is limited. When canvassing on the doorstep, it is not a “hot button” topic. Nor is it for the media – apart from when individual tragedies come to light.

The social work establishment is hostile to adoption and so make no complaint about the figures. Ministers who wish to be “friends of the sector” find it prudent to let matters drift. Under Jeremy Corbyn, the Labour Party is on the same ideological wavelength. It would be pretty hard to qualify as a social worker without writing essays in line with a Corbynista world view.

Yet taking a broader view, reducing the number of children in care should be a political priority. A quarter of prisoners spent their childhoods in care. That equates to children in care being 50 times more likely to end up in prison when they grow up than other children. Boosting adoption is the most effective policy for fighting crime.

Opportunities have also been missed to improve the outcomes for children in care. The number offered the chance to attend boarding school is pathetically small. If children are in care, it is better for them (and much cheaper for the taxpayer) to be placed with foster carers rather than institutional children’s homes, where this is possible. Yet the number placed in children’s homes has not been kept to a minimum – as evidenced by the significant proportion of such children in mainstream education and thus for whom foster placements would clearly be viable.

What about preventing children needing to go into care in the first place? This brings in much wider subjects – housing, education, welfare, crime. Here the Troubled Families programme has made an important contribution.

Is there any hope of future improvement? The Conservative Manifesto says:

“Children who end up in care are more likely to struggle as adults, denied the love and stability most of us take for granted. We will prioritise stable, loving placements for those children – adoption where possible or foster parents recruited by the local authority. We will review the care system to make sure that all care placements and settings are providing children and young adults with the support they need.

“A strong society needs strong families. We will improve the Troubled Families programme and champion Family Hubs to serve vulnerable families with the intensive, integrated support they need to care for children – from the early years and throughout their lives.”

That is fine so far as it goes. But to get tangible progress, robust legal changes will be needed to establish a presumption in favour of adoption for children in care. Relying on the goodwill of social workers – seeking to persuade them or to give them more money – has proven ineffective. The challenge can be met with determination and courage. Bland and worthy platitudes will just mean thousands more lives will be ruined as the expensive conveyor belt from care system to prison keeps cranking along.