... several Whitehall sources told "The Times" that Mr Brown did not like some of the advice he received from Sir Nicholas, including some "home truths" about long-term trends in the economy and he never broke into the chancellor's tight-knit inner circle. ... He subsequently lacked a real role and spent most of his time working on major international reports on global warming and alleviating poverty in Africa. His doom-laden report on the risks of failing to address climate change, published in October, caused tensions within the Government by triggering a debate on environmental taxes and leading to calls for big policy changes.