The Government's "pupil premium" is making a real difference to children from the poorest families, Education Minister David Laws will insist today as he announces it will rise to £900 per pupil next year.
Mr Laws admitted earlier this week that the use of funds from the Government's flagship policy was "not good enough" after the education watchdog said more needed to be done to make sure the money was used to help deprived youngsters.
Sir Michael Wilshaw, Ofsted's chief inspector, said there was real concern that funds were being used simply to "plug the gap" in school budgets as more than half of schools surveyed said it was making "little or no difference".
In his first Liberal Democrat party conference speech after making a frontbench comeback in the reshuffle, two years after being forced out over the misuse of taxpayer-funded expenses, Mr Laws will hail the scheme.
Next year's rise - up from £619 per pupil this year - will see £1.8 billion allocated to the premium with the Government on track to allocate £2.5 billion a year in 2014/15, or around £1,200 per pupil.
And he will tell restive activists gathered in Brighton for the annual gathering that that means "fully delivering the manifesto pledge that Nick Clegg made in May 2010".
The party wants the pupil premium to be seen by voters as one of its achievements within the Tory-led coalition.
Mr Laws will warn that there remains "far to go" to extend opportunity to every young person in Britain's state schools - calling the numbers achieving five good GCSEs a "national disgrace".
"Opportunity cannot only extend to the boundaries of the playing fields of Eton, or even Westminster," he will add - in a reference to the exclusive public schools attended by Prime Minister David Cameron and his own party leader.
"It must be available in every school, in every community, in every part of our country. We are moving from an education system which entrenched privilege, to an education system which will hand opportunity to every child.
"And not before time. Our ambitions in education must be big and bold, because there is still so far to go."
Fewer than four in 10 children achieved the "basic minimum qualification level" at GCSE, he said.
"This is a huge waste of talent; it is a national disgrace and it must change," he will declare - saying the minimum first step must be for all schools to get at least 80% of children to that benchmark level.
Announcing the scale of next year's rise, he will add: "Just think what we have done with that policy."
Schools get extra cash for every child registered as eligible for free school meals (FSM) and children in care.
Earlier this week Sir Michael Wilshaw said the watchdog had been surprised by the survey results. Only 10% of schools surveyed said it was having a "significant" effect, all of which were in the most deprived areas.
The DfE said latest statistics show that in 2011, 35% of pupils on free school meals achieved five good GCSE grades, compared with 62% of other pupils, while 58% of pupils on free school meals achieved the expected level in both English and maths by the end of primary school, compared with 78% of other pupils.
It said while schools have freedom to use the funding in innovative ways, they should use it to boost results for the most disadvantaged pupils and will be held to account by Ofsted.
The DfE also announced that the Government is making £50 million available for a summer school scheme for Pupil Premium pupils to run again next year.
Chris Keates, general secretary of the NASUWT, the largest teachers' union, said: "The announcement of additional funding for the most disadvantaged pupils is of course to be welcomed.
"However, the devil will be in the detail of this announcement. In the context of cuts to school budgets and public spending where is this additional money coming from to fund the increase in the pupil premium?
"If cuts are simply being made elsewhere to provide the illusion of additional money then this will be little more than a cosmetic exercise which will fail to provide support to those who most need it and deprive others of much needed funding."
Anne Longfield, chief executive of the 4Children charity, said: "This increase in funding is welcome but the money must be spent on what the evidence shows works - extra support in school and support for families to help their children learn.
"We know that not all children come into the classroom ready and able to learn. Schools need the extra funding to pay for high quality staff to spend more time working with children who need extra support at school and at home in the family. This needs to be at the centre of schools' pupil premium strategies to improve outcomes and make social mobility a reality."