A generation of young people could "miss out" on the best start to life unless the Scottish Government reviews its nursery education policy, according to Liberal Democrat leader Willie Rennie.
He appealed to Deputy First Minister Nicola Sturgeon to follow the example in England, where he said four in 10 of the most disadvantaged two-year-olds will get some free education.
Expanding provision will help bridge the gap between rich and poor, he said during First Minister's Questions at Holyrood.
"In England, they're going to give nursery education to 40% - four out of 10 two-year-olds will be getting nursery education," he said.
"In Scotland, it is only one per cent. A generation will miss out. The evidence is that many will never, ever, catch up. It's a gap in provision that will lock in a gap in attainment."
The Scottish Government wants to increase free early learning and childcare from 475 hours to a minimum of 600 hours per year, an increase of 45% in provision since 2007.
Ms Sturgeon, standing in for Alex Salmond, said nursery education has been extended, as has entitlement to free school meals.
"I do believe that is a sound package of support but I also accept that, particularly for the most vulnerable children, and the youngest of the most vulnerable children, we've always got to be working to do more to increase the support and make sure we're giving our youngest children the best possible start in life," she said.
Responding to the English comparison, she told MSPs: "The package of early years care that this Government is pledged to deliver is greater than what is being delivered south of the border. The Government in England is not providing 600 hours per year of childcare."
Despite the differences, Ms Sturgeon said she hopes for cross-party consensus on the issue.