Tens of thousands of extra school places will be needed by next year amid a continuing surge in demand, the Nation Audit Office said.
Ministers will visit schools in London today to see the problem for themselves.
According to Barking Council, an estimated 1,000 extra primary school places will be needed in Barking each year, in line with projected population growth.
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Nick Clegg will attempt to win over the female electorate when he kicks off the Liberal Democrats' general election campaign later today.
Up to £140 billion of savings could be released when over 55-year-olds are allowed to cash in their pension pots from April 6th.
The party's plans include a £2.5 billion Time to Care fund for the NHS, capping rail fare increases and 3,000 more midwives.