Children in care in England still lag way behind their peers, despite new figures showing a slight improvement in their performance.
Children in care often face multiple school moves
A third of looked after children reached age 16 in 2006 without any qualifications compared to only 2% of all children that age.
And only 12% gained the benchmark five good GCSEs last year, compared to 59% of their peers.
The government said it would be publishing plans to address the issue.
The Department for Education and Skills had aimed to get children in care achieving school exam results which are at least 60% as good as those of their peers by 2006.
This would have meant 31.8% of children in care achieving five or more good GCSE grades.
This aim clearly has not been met, although the number of children in care gaining one GCSE or GNVQ is up three percentage points on the 60% who gained one qualification in 2005 and 7% on the 56% who did so in 2004.
There are also small improvements in the proportion of looked after children gaining the required level in English and maths at age 11.
Some 54% reached level 4 in 2006 compared to 52% in 2005 and 52% in 2004.
But looked after children's record of achievement appears to get worse as they progress through the education system.
Some 58% achieve the required standards by the second year of primary school, but this drops to 47% by the end of primary school and 30% by the end of Key Stage 3 (age 14).
This compares to 85%, 81% and 74% of all children respectively.
Education Secretary Alan Johnson has repeatedly referred to the underachievement of looked after children, saying that it should not matter where a child comes from, that they should still be able to achieve.
In August last year, he said: "Children in care already face a tougher life than any child should have to.
"As a proxy parent, the state must raise its ambitions for these children, just as a good parent would, and transform their life chances through better emotional, practical and financial support at home and in the classroom.
At the same time he proposed plans to oblige schools to accept children in local authority care even if they are full.
And existing admissions rules say looked after children should be given priority over other children.
A Department for Education and Skills spokesman said it spent £1.9bn annually on supporting children in local authority care.
"We recognise that although educational outcomes for children in care are slowly improving, the current situation is not acceptable and that much more must be done.
"That is why we will publish a white paper later this year."
Shadow minister for children, young people and families Anne McIntosh welcomed the slight improvement, but said it was particularly worrying "that cautions and convictions for looked after children are on the rise, and unemployment among children in care at 16 has not improved at all."
Research for children's charity Barnardo's suggests multiple care home and foster care placements, repeated school changes, exclusion and insufficient support all make doing well at school more difficult for children in care.