The Islamic movement Hamas is taking over from Fatah, the party created by Yasser Arafat, as the main Palestinian national organisation as a result of the war in Gaza, says a leading Fatah militant. "We have moved into the era of Hamas which is now much stronger than it was," said Husam Kadr, a veteran Fatah leader in the West Bank city of Nablus, recently released after five-and-a-half years in Israeli prisons.

"Its era started when Israel attacked Gaza on 27 December."

The sharp decline in support for Fatah and the discrediting of Mahmoud Abbas, President of the Palestinian Authority, because of his inertia during the 22-day Gaza war, will make it very difficult for the US and the EU to pretend that Fatah are the true representatives of the Palestinian community. The international community is likely to find it impossible to marginalise Hamas in reconstructing Gaza.

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"Hamas has been highly successful in portraying itself as the party of the resistance, and Fatah and Mahmoud Abbas as the opponents of resistance at a time [when] the public wants to resist," said Ghassan Khatib, a former Palestinian minister of planning. He adds that Mr Abbas was badly damaged in the eyes of Palestinians when he blamed Hamas for Israel's assault on Gaza in the conflict's first two days.

Mr Kadr, who says he was tortured by Israeli interrogators during detention, does not welcome Hamas's triumph. But he is convinced that, just as Fatah's long reign was launched by the battle of Karamah in March 1968, when Fatah fighters aided by the Jordanian army, repelled an Israeli attack on their HQ in the Jordan valley, so Hamas will gain from the Gaza war. "The Hamas era comes 40 years after Karamah began the Fatah period," he says.

Hamas is conscious of its political success even if it was able to do little against the Israeli army. Mr Khatib, in his office in Ramallah, the Palestinian capital on the West Bank, says the first priority must be the formation of a Palestinian unity government between Hamas and Fatah. But he adds gloomily that "the chances of this happening are slim" because the Gaza war has exacerbated hatred between the two sides as Fatah supporters are hunted down and sometimes executed in Gaza.

Aside from Gaza there is another reason why President Abbas and Fatah are weak. Long years of negotiations with Israel have achieved nothing while red-roofed Israeli settlements have sprouted on every West Bank hilltop. Driving into Nablus, a city of 250,000 people that was once the bustling heart of the West Bank, the streets are empty and row after row of shops are shut.

"We had eight years of complete closure when people could not get in or out of Nablus aside from the 3 per cent who had permits," complains the city's mayor Adly Yaish. "Most factories shut and 60 per cent of people live below the poverty line." The closure became a little looser three months ago, but yesterday there were long lines of vehicles at the Israeli checkpoints around the city.

The rise of Hamas and the demise of Fatah is best explained by the failure of President Abbas to achieve anything through negotiations for ordinary Palestinians. "We in Fatah have failed to remove a single Israeli checkpoint," admits Mr Kadr. "It takes me as long to reach Ramallah 50 kilometres away as it would to fly from Jordan to Ankara."

He believes the Gaza war has spread the seeds for another Palestinian uprising. "The coming uprising will be very hard for both the Palestinians and the Israelis," he warns, though he does not forecast when it will occur. He points to a television in his office on which a young Palestinian girl called Dalal is shown picking through the ruins of her house in Gaza where all her family had died and only her cat had survived. "Can you imagine how Palestinians feel when they see this?" he asks.