The Scottish Government has suffered a parliamentary defeat amid criticism of its manifesto pledges on education.
Opposition parties were critical on SNP pledges
MSPs rejected the SNP's stance by 76 votes to 48.
Instead, the Scottish Parliament backed a motion demanding an explanation of how the administration would deliver smaller class sizes.
However, Children's Minister Adam Ingram accused Labour of "relentless negativity" and of resorting to the politics of "smears and jeers".
The motion passed by parliament also called on the SNP to deliver on its manifesto commitment to increase nursery education.
In an earlier debate, Labour education spokesman Hugh Henry, along with the Tories and Lib Dems, attacked the Nationalists, accusing them of failing to deliver on key pledges.
The former education minister said: "It doesn't matter that they could deliver many of these without securing a majority in parliament, it is simply a case of trying to blame someone else for their inability and unwillingness to deliver - some may call it naivety, others may call it plain deception."
Mr Henry criticised the current administration for failing to outline how it would support universities and failing to deliver on a pledge to write off student debt.
"The sum total of the story so far is over-promised under-delivered, worse - it's promises they couldn't keep, they were prepared to say anything to get elected," he added.
"Politicians have a bad name but the SNP have reached new depths in posturing, spin and downright deception."
Mr Ingram said the government was determined to stop the "criminal waste of human potential" holding back Scotland.
He said: "Ten years of Labour rule, with Liberal Democrat support for most of them, and absolutely no improvement in attainment levels of the lowest performing 20% of the school population - the vicious cycle of poverty and deprivation, lack of qualifications, low pay and unemployment unbroken."
The minister said the SNP had made a good start, but insisted government was about "years, not days".
"I know that parliamentary colleagues will be interested, indeed impatient, to hear more detail on implementation," he added.
"However, they will have to be patient for just a bit longer, until we can complete the spending review."
Liberal Democrat education spokesman Jeremy Purvis said First Minister Alex Salmond claimed last week the class size reduction for P1 to P3 would be met within four years, and that the Scottish Government would also deliver on its election pledge to remove the burden of debt on Scottish students.
"More work needs to be done and the government needs to come back with a clear statement on how it will deliver its much vaunted promises," he said.
Liz Smith, the Tory schools spokeswoman, said her party had "grave misgivings" about the Nationalists' ability to deal with education.
She questioned the SNP's plans to cut class sizes for the first three years of primary school to 18.
"This policy is simply not sustainable and it should not be paraded as a one-size-fits-all panacea that will drive up education standards," she said.
"Effective learning is first and foremost about good teaching in a calm and disciplined environment and there are many circumstances where parents would opt to have their child taught in a slightly bigger class if it meant better teaching, better discipline and access to a better school," said Ms Smith.