He also announced changes to introduce greater flexibility to allow more parents to take advantage of the scheme – already used by more than 800,000 three and four-year-olds.
It is intended that 150,000 of the most disadvantaged two-year-olds will receive up to 15 hours a week of free pre-school education from September 2013, rising to 260,000 in 2014.
Chancellor George Osborne announced in his 2010 spending review that the free childcare currently available to three and four-year-olds would gradually be extended to two-year-olds in England.
Following a consultation, Mr Clegg announced yesterday that the first areas to benefit, in September this year, will be Rotherham, Blackpool, Cornwall, Greenwich, Kent, Lambeth, Lancashire, Newcastle, Northamptonshire and Peterborough.
Parents will be given the option to spread their free nursery place over two days, rather than three, and to use the free hours between 7am and 7pm, rather than 8am and 6pm. The changes are intended to make it easier to fit the childcare around working lives.
New guidance will also make clear that nurseries cannot make the free childcare conditional on parents also taking up additional paid-for hours.
Mr Clegg, MP for Sheffield Hallam, said: “We’re revolutionising the early start our children get in life – there will be more free childcare, it will be higher quality, and it will be more flexible for parents.
“By getting things right from the off, we’re making sure our youngsters are ready to learn when they start school so that they get the most out of their education.”