LONDON: Prime Minister Gordon Brown said Britain could reduce its nuclear arsenal as part of a global disarmament deal to persuade Iran and North Korea to give up its nuclear ambitions, reports said.

Speaking to reporters at the G8 summit in Italy, Brown said US-brokered talks next year could pave the way for Britain to reduce its warhead numbers in return for Tehran and Pyongyang abandoning nuclear programmes.

Brown stressed the government had no plans to unilaterally abandon its 160-warhead Trident arsenal or scrap plans to replace the fleet of submarines that act as its platform, The Times said.

The prime minister said "collective action" was needed in an attempt to dissuade both nations from acquiring nuclear weapons.

"Iran is attempting to build a nuclear weapon. North Korea is attempting to build a nuclear weapon. We have got to show we can deal with this by collective action," he said.

"Unilateral action by the United Kingdom would not be seen as the best way.

"What we need is collective action by the nuclear weapons powers to say that we are prepared to reduce our nuclear weapons, but we need assurances also that other countries will not proliferate them."

Brown -- who flagged earlier this year that Trident could be on the table as part of any multilateral arms reduction negotiations gave no details of the size of any cut in the British deterrent, the Daily Telegraph said.

Group of Eight leaders meeting at their summit in Italy agreed to US President Barack Obama's proposal that a nuclear security summit should be held in Washington ahead of the planned review of the Non-Proliferation Treaty.