But ending poverty is also vital in raising pupils' achievement, says Lib-Dem leader Nick Clegg.
Give good teachers more funding to help disadvantaged pupils and you cannot fail to raise standards, according to the Liberal Democrats' new leader.
Nick Clegg sees breaking the link between poverty and achievement as the key to ensuring all secondaries reach his minimum "acceptable" standard of more than half of pupils passing at least five good GCSEs.
But in an interview with The TES, Mr Clegg admitted it was teachers who made the biggest difference. "I love visiting schools," he said. "And what I find most striking is that, whatever the politicians and policy wonks say, a relatively small number of dedicated, enlightened teachers can, under almost any system and sometimes despite the system, produce a community of very happy and motivated children."
With his public schoolboy haircut and sober tie, the Westminster School-educated Cambridge graduate, who has not ruled out privately educating his sons, could be mistaken for a Tory. Some might say the same for his education policies.
His flagship "free schools" plan even shares the same name as an earlier ill-fated Tory policy, and it echoes a well-worn Conservative theme: allowing parents to set up their own schools, free from political interference.
But the 41-year-old argues that this idea, and a hands-off approach from Whitehall in the day-to-day running of schools, is the kind of classical liberalism his party - which once called for an extra penny on income tax to fund education - should be reclaiming.
What extra freedoms these schools would have is unclear. Admissions would remain closely controlled, with an "end to selection" (but not in grammars), and the core curriculum would be decided centrally. Schools are already responsible for running their own budgets, but under the Lib-Dems town halls would stage a comeback, gaining "strategic oversight" over all schools, including academies.
Mr Clegg is clear on the pupil premium, which he says would bring spending per head for the 14.5 per cent of pupils eligible for free school meals up to independent sector levels.
But if it does not have the effect on standards he expects, what would a government committed to staying out of the day-to-day running of education be able to do?
"The evidence from countries such as Sweden, Finland, Denmark and the Netherlands is that we will reach our targets if we implement these policies."
Clearly, failure is not an option.
Clegg's policy plans
- Parents, charities and private companies allowed to set up "free schools" to innovate without government interference.
- Pupil premiums worth pound;2.5 billion a year to bring funding for the poorest pupils up to independent sector levels.
- Qualifications and Curriculum Authority, Ofsted and parts of the Department for Children, Schools and Families to merge to create an Educational Standards Authority independent of ministers and accountable to Parliament.
- Abolition of F and G GCSE grades because these are "of no value in today's labour market".