The Plain English campaign’s recent complaints about the inappropriate use of language in politics has missed the main target. There is no more misleading euphemism in public policy than “looked-after children”, the new term for what used to known as children in care.

The care system in Britain is expensive and ineffective. Around 60 per cent of children in care leave school with no qualifications. They are 50 times more likely to end up in prison than their peers. Neither is there any real relationship between performance and spending. Local authorities now spend £40,000 a year for every child in care. Yet there has been almost no improvement in their educational achievement in a decade. That is why it is especially discouraging news that the number of adopted children who have been returned to the care system after a failed attempt at adoption has doubled in the past five years.

British law enshrines the laudable principle that children should be kept in their natural families. Under the Children’s Act 1989 local authorities were specifically given the task of promoting “the upbringing of children by their own families”. To uphold family life is a laudable principle. But it is not the sovereign value and more than three quarters of adopted children have been victims of abuse or neglect, usually at the hands of parents with alcohol or drug problems.

This presumption often means that children are kept in their birth family for too long. Lord Laming has also pointed out that court fees for applying to take children into care can be a deterrent, falling, as they do, on councils. The Adoption Act 2002 was expressly designed to expedite the adoption process but a 2006 government study found that delays in entering the care system still significantly reduced the chances of a viable adoption.

As a consequence, when children are finally placed in their adoptive families, their problems have been simmering for too long. Then, the support on offer for adoptive parents is inadequate. The Children (Leaving Care) Act 2000 introduced personal advisers to help care leavers to prepare for independent living. The formal system is not working well enough.

The best solution is fostering. The average cost per child in care is £774 per week. For children in residential homes the average is more than £2,000. For foster care it is just £489. The system, however, is 10,000 people short. Worse, more than 90 per cent of foster carers are over 40. Since 2007 there has been a national minimum for allowances but this has by no means been implemented universally. Forty per cent of foster carers receive no fees at all and 75 per cent are paid below the national minimum wage.

The combination of an overloaded system, recalcitrant children and inexperienced parents is not one that we should expect to work very often. In a sense it is a surprise that these disappointing figures are not worse than they are. The most important factor for a child in care is a durable attachment to a trusted adult. When this is lacking, as too often it is — one in ten children is moved nine or more times — progress is all but impossible. Philip Larkin once said that an only life can take so long to climb clear of its wrong beginnings, and may never. We have a duty of care to these children and it is not being exercised.