The 2008 Budget was 'a green cop out' that 'kicked the difficult decisions on environmental taxes into the long grass' and displayed 'fiscal incompetence and political desperation', the Liberal Democrats have claimed.
The party's leader, Nick Clegg, said the Chancellor's plans offered 'no help to the millions of hard pressed families struggling to make ends meet'.
Mr Clegg went on to claim the Budget was 'a con trick' and that the Government had 'bottled it on green taxes and failed to implement the necessary measures to cut child poverty.
He added: 'This was an opportunity to give whatever help possible to millions of stretched British families who are feeling the pinch; whose money just doesn't go as far as it used to.
He said that the Budget gave 'only limited help to the poor' while maintaining 'special treatment for the rich'.
It was, claimed the Lib Dem leader, 'a Budget designed to fill a black hole masquerading as good for the environment; a Budget which will not make Britain fairer, and a Budget that is a great green cop out, as most of the new green taxes are being delayed'.
He returned to the subject of child poverty: 'The piecemeal reforms that the Chancellor is introducing to the chaotic Tax Credit system won't get the Government anywhere near meeting its 2010 Child Poverty target.
'The reality is that the Government's approach has failed. If we are to abolish child poverty for good we must not only increase income we must increase opportunity too.'
Mr Clegg then turned again to Alistair Darling's attempts to address environmental concerns.
'Green taxes should be revenue-neutral. They should not be treated as a wheeze to squeeze ever more money out of the British people, but should instead be designed to encourage green behaviour, and to cut the taxes of the most needy.
'This [was] not a Budget for the environment. [It was] a Budget driven by fiscal incompetence and political desperation.'