Brown's address to the Israeli parliament, the first ever by a British prime minister, rounded off his two-day visit to Israel and the West Bank.
"Iran now has a clear choice to make: suspend its nuclear program and accept our offer of negotiations or face growing isolation and the collective response not just of one nation but of all nations round the world," Brown said.
"Just as we have led the work on three mandatory sanctions resolutions of the UN, the UK will continue to lead - with the United States and our European Union partners - in our determination to prevent an Iranian nuclear weapons program."
Referring to Iranian President's Mahmoud Ahmadinejad's infamous call for Israel to be wiped off the map, he said: "To those who believe that threatening statements fall upon indifferent ears we say in one voice - it is totally abhorrent for the president of Iran to call for Israel to be wiped from the map of the world."
He voiced his support for Israel, saying: "For the whole of my life, I have counted myself a friend of your country," and called the U.K. and Israel allies in the "fight for liberty".
Brown's speech comes against a backdrop of growing tensions between Iran and Israel, highlighted by military exercises and weaponry tests widely seen as demonstrations of power before a possible war.
International negotiations on Iran's nuclear program have so produced little result.
After the latest meeting, held on Saturday between Iran and six world powers, European Union foreign policy chief Javier Solana said 'Iran Six' was expecting a clear answer from Tehran in about two weeks to their offer of trade and technical incentives to halt uranium enrichment.
Iran is currently under three sets of relatively mild UN Security Council sanctions for defying demands to halt uranium enrichment, which it says it needs purely for electricity generation despite Western accusations that the program is geared toward weapon production.
