David Cameron has unveiled a radical overhaul of the care system that includes significant changes to adoption laws and social services.
The Prime Minister called for "zero tolerance of state failure" as he highlighted worrying trends of children who are placed in care falling into crime, the sex trade and homelessness in later life.
Writing in The Sunday Times ahead of the Queen's Speech on Wednesday, Mr Cameron pledged to provide care leavers with extra support into adulthood that is enshrined in a covenant and announced the creation of a new social care watchdog.
Local authorities will also be made to assist care leavers in finding housing, jobs and healthcare, while each person will be assigned a mentor until the age of 25.
There will also be wider support in the form of new programmes including an initiative with the Arts Council to help broaden care leavers' horizons.
The Prime Minister said the Government shared the feeling of impatience with the current system with those who have been let down by it.
He said: "For too long, whether through misguided notions of what is right or sensitivities about not wanting to cause offence, we have let the most vulnerable in our country down."
The reforms are part of a legislative programme Mr Cameron said will bring about a "great social transformation in Britain" that includes opening up educational opportunities, a shake-up of the prisons system and new powers to tackle extremism and segregation.
His proposals for the care system begin with a fundamental change to the adoption process, involving a departure from a current trend in the family courts that promotes children being placed with distant relatives rather than adoption by new families.
While praising the work of foster parents, he cited a near 50% fall in adoption numbers over the last two years and said new laws would "tip the balance" in favour of permanent adoption in the right circumstances even when that means over-riding family ties.
Mr Cameron said he was "unashamedly pro-adoption" and the move would be vital as greater importance will be attached to "long-term stability and better outcomes".
The Government previously changed rules that effectively prevented black, mixed-race or Asian children being adopted by white parents. Changing the "nonsensical" law led to a 72% rise in adoptions, he said.
Having brought in new powers to intervene where local authorities are deemed to have failed in a child's care, the Prime Minister said he now wants to reform training for social workers by cutting red tape.
The Prime Minister said he believed that by introducing vocational courses and reducing time spent in classrooms, social workers will be better equipped to use their experience to provide the best care and intervene when there is a risk of failure.
A regulator will oversee this new system and ensure a set of standards is met in each case by 2020.
Once an individual has left the care system they will continue to receive support under a care leavers' covenant, including practical help in finding jobs and managing money. Business will also be invited to take part and apprenticeship funding will be extended to 25 for care leavers.
Mr Cameron said those leaving care needed "far more support" but it was not solely the Government's responsibility.
He added: "These are not someone else's children; they are all of ours so every part of society should be stepping up to help care leavers get a shot at building a decent life."