I had assumed the laughable ineptitude of the Chuckle Brothers, with their hilarious catchphrases "To me, to you" and "Oh dear, oh dear" was an act devised for their children's television programme.

But after hearing about the social services department in Rotherham, I begin to wonder if moronic incompetence is a widespread character trait in their home town. Rotherham's Labour-controlled Metropolitan Borough Council has now decided to review the case of the foster parents who, on the basis that they were supporters of the UK Independence Party, had three children removed from their care, but the town's director of children and young people's services, Joyce Thacker, is still attempting to justify her decision, though the Education Secretary, Michael Gove, correctly described it as "indefensible".

No doubt some UKIP supporters are racist, but then so are some Conservative and Labour voters. But the party itself has no racist policies (it is fielding a black candidate in Croydon North) and there seems to be no suggestion at all the couple involved have any such prejudices. As they point out, had they been racists, they would hardly have been keen to give the children a home, nor to take the trouble to learn some of their native language and ensure their school fitted in with their religious background.

One can readily see that UKIP, which gives the general impression of being the political wing of a Home Counties golf club, would not appeal to the bien-pensant lefty sensibilities of your average social worker. As it happens, though I heartily approve of UKIP's views on the EU, and share some of their scepticism about multiculturalism, their policies on immigration don't appeal to me either. Because I believe in free trade and the removal of tariff barriers, I'm in favour of the free movement of labour and think immigration has been mostly beneficial for Britain.

What would never have occurred to me, or to anyone with a quarter the wits of a Chuckle brother, was that support for a mainstream political party (only a few days ago they came third in the Corby by-election, with four times the vote of the LibDems) would be cited as justification for declaring anyone unsuitable as foster parents. What is even more incredible is that Rotherham social services, so vigilant and wrong-headed in this case, was also the department responsible for doing nothing about the grooming of under-aged girls in care by a ring of criminal perverts. Indeed, on several occasions the victims of this abuse were treated as criminals.

The suggestion made in that case was that the authorities had failed to act because the men involved were Asian, but to blame this grotesque incompetence, or the idiotic decision in the UKIP case, on political correctness alone is to risk losing sight of the fact that too many people involved in the care system have even more fundamentally misguided priorities.

Of course there are many hard-working, committed and sensible people trying to do their best for children at risk or in care. But the statistics paint a terrifying picture. One-third of children in care leave school with absolutely no qualifications at all; only 6% go on to university. One-third of care leavers are not in education or employment (compared with 13% of all young people), while almost one-third of all adult prisoners, and nearly 40% of those under 21, spent time in care as children.

This is nothing short of a national scandal. It is the more appalling because all the evidence suggests that, on every measure, children who are adopted or fostered do better, and there are huge numbers of people willing and ready to adopt. It is only right that there should be some checks to ensure prospective adoptive parents will prove suitable, but the fact is that all children brought up by their natural parents are already being raised by unvetted, and possibly even unsuitable, people.

Yet whatever these parents are like – UKIP voters, smokers, homosexuals, people who can hear Nicola Sturgeon's voice without wincing, estate agents, Moonies or any other group you may think unsuitable – they almost always do a better job than the state. If that isn't a damning systemic failure, it's hard to see what qualifies.

Mr Gove (who was adopted himself) sensibly said: "We should not allow considerations of ethnic or cultural background to prevent children being placed with loving and stable families. We need more parents to foster, and many more to adopt." It's difficult to get precise figures for children in care across the UK, because each of the home nations assesses them slightly differently (the 16,000 or so children listed in Scotland includes, for example, those under supervision orders, which may mean they are living in the family home). Almost 90,000 children are in the care system across the UK, yet last year only just over 3000 children were placed with new families. During the 1970s, that figure was around 20,000 annually.

The figures suggest that seven of every eight prospective adopting couples either abandon the attempt, because they find the process so difficult to negotiate, or are turned down flat by the authorities. This is lunacy. Of course it is important to be on guard for grossly unsuitable applicants, but unsuitability should mean dangerous criminality, convictions for violence, heroin addiction and similarly extreme failings, not being the "wrong" colour, or not having a television set, or not liking football.

All sorts of odd people bring up children more or less successfully, as we know because, in the normal run of things, they do. There have been recent, tragic cases of natural parents harming their children. These are mercifully rare, but the evidence suggests that it is equally rare among adoptive parents. Yet tens of thousands of people are being denied the chance of an ordinary upbringing by the wickedness of officials who elevate their own ideological preferences above the welfare of children. The only people who seem obviously unsuitable to look after children in this case are Rotherham social services.