DAVID CAMERON’s plans to double free childcare for all English working parents’ three to four-year-olds to 30 hours a week are likely to throw up trouble, education experts said yesterday.

The Prime Minister has admitted it will “take time” for the idea to work amid warnings from pre-school professionals who have said that the system faces “meltdown” unless the changes are fully funded.

Ministers say up to 600,000 families will eventually benefit from the move, which comes into play in September 2016.

The extra care is worth around £2,500 a year on top of the £2,500 parents can already save from the existing hours.

But the Pre-School Learning Alliance, representing 14,000 groups, warned that the existing free hours were already “grossly underfunded.”

Research for the charity has suggested that the total cost to the sector will be approximately £1.95 billion per year, but funding at current rates amounts to £1.7 billion.