TONY EASTLEY: Former Australian prime minister John Howard has likened some people's belief in global warming as akin to religious fervour.

Mr Howard was speaking at a press conference ahead of his keynote speech at the Global Warming Policy Foundation in London, a controversial organisation accused by its detractors of being made up of global warming deniers.

Europe correspondent Philip Williams was at Mr Howard's media conference.

PHILIP WILLIAMS: Titled One Religion is Enough, John Howard says while he respects sound science he is an agnostic when it comes to the causes and effects of global warming.

JOHN HOWARD: I am opposed to putting a ludicrously heavy financial burden on often poorer people in the community in the name of shifting to renewables when I'm unconvinced that catastrophe is around the corner.

PHILIP WILLIAMS: Mr Howard said developing countries like India and China should not be pressured to moderate energy consumption if it risks future prosperity.

JOHN HOWARD: I still think that the most exciting thing the world can do in the next 20 years is lift a few hundred more million, perhaps a couple of billion people, out of poverty by economic growth and globalisation. To me that's far more exciting than some of the things that people are recommending on global warming.

PHILIP WILLIAMS: Mr Howard is clearly excited about the possibility of shale oil and gas fracking and for another controversial energy source.

JOHN HOWARD: My argument is that the nuclear option should be kept on the table and as it becomes more economic to have nuclear power we should entertain it.

PHILIP WILLIAMS: There was one well known Australian who couldn't make it to John Howard's lecture. WikiLeaks' Julian Assange is still stuck in the Ecuadorian embassy in London.

JOHN HOWARD: I don't think he merits an enormous amount of publicity but I certainly don't take the view that he's some kind of huge criminal; I just think he's an opportunist.

PHILIP WILLIAMS: John Howard did put a toe in the British political waters, defending the role of Australian Lynton Cosby as strategy advisor to the Conservative Party in the UK and rebuking UK opposition leader Ed Miliband's attack on Cosby's role in the Cameron government .

JOHN HOWARD: I saw that and I thought that was just pathetic. I mean if you're the alternative prime minister of a country and you are using a platform to attack the activities of a political advisor and campaign director in another country, you display an odd sense of insecurity.

PHILIP WILLIAMS: Insecurity a condition not often attributed to John Howard.

This is Philip Williams in London reporting for AM.