Environmentalist Jonathon Porritt was also among the guests at Buckingham Palace on Tuesday to receive a CBE.

BBC: Liz Dawn

An influential friend of the Prince of Wales, Porritt is now the prime minister's chief adviser on the environment as chairman of the government's sustainable development commission.

BBC: Liz Dawn

"Barack Obama's running mate sunk to a new low today, launching an offensive debate over who cares more about special needs children, " McCain-Palin spokesman Ben Porritt said.

CNN: Biden's comments on special needs kids called 'new low'

The study, carried out by Jonathon Porritt, former head of the Sustainable Development Commission, said the government had scrapped a planned rise in aviation tax, failed to create a green investment bank with immediate borrowing powers and had watered down schemes promoting small-scale renewable electricity.

BBC: Clegg: UK green bank 'to begin investing in April 2012'

"Rest assured that, despite these threats, the McCain-Palin campaign will continue to address the serious issue of voter registration fraud by ACORN and other partisan groups, and compliance by states with the Help America Vote Act's requirement of matching new voter registrations with state data bases to prevent voter fraud, " Porritt added.

CNN: Obama camp calls for special prosecutor in fraud investigation