Chancellor Rishi Sunak has been accused of offering "completely inadequate" post-lockdown support to pupils with government help for schools being done "on the cheap".
The chancellor also set out new funding of £1.8bn to help schools and colleges in education recovery following the COVID crisis.
This brings the government's total funding for school catch-up efforts after coronavirus lockdowns to £4.9bn.
But critics pointed out - even with the extra cash - how the sum is still less than a third of the £15bn asked for by the government's former education catch-up tsar, Sir Kevan Collins.
Kevin Courtney, joint general secretary of the National Education Union, claimed Mr Sunak was "still determined that education recovery will be done on the cheap".
He said: "With just £2bn added, the government's plan for education recovery is completely inadequate.
"Recovery tsar Sir Kevan Collins proposed a £15bn package and resigned when it was rejected.
"Even with the announcement today, the chancellor is operating at around a third of that price. This is simply not good enough.
"Recovery will take years of work and investment."
Geoff Barton, general secretary of the Association of School and College Leaders, said the new funding announced by Mr Sunak was "nowhere near what is needed".
"We will continue to press for the education recovery funding that children need and deserve," he added.
"They have suffered the most educational disruption of any generation since the second world war and the government must do better for them."
Paul Whiteman, general secretary of school leaders' union NAHT, said: "Children and young people have been hugely affected by the pandemic.
"The government has made bold claims about 'levelling up' and 'no child left behind'. The investment announced today doesn't meet those goals or the future needs of the country."
Labour's shadow chancellor Rachel Reeves claimed the government had "no serious plan to catch up on learning" lost during the pandemic.
And Liberal Democrat leader Sir Ed Davey said: "Parents are crying out for the catch-up funding our children desperately need.
"The chancellor let them down today, offering less in extra catch up funding than his tax cut for the big banks."