Chancellor George Osborne has cut his official growth forecast in half, but insisted the UK would avoid a "triple dip" recession.
He said growth in 2013 would be 0.6%—half the 1.2% he predicted four months ago in his autumn statement.
But he cut the headline rate of corporation tax by 1% to 20%, which taken with earlier cuts he said was the biggest ever reduction.
Mr Osborne said his Budget was for "those who want to work and get on".
He said it was taking longer than expected but "we are, slowly but surely, fixing our country's economic problems".