Ehud Olmert declared himself satisfied yesterday with the outcome of their first meeting in London since becoming Israel’s prime minister in which Mr. Blair signaled an important shift in British policy.

For the past three years, Mr. Blair has been a staunch advocate of the “road map” for a negotiated settlement in the Middle East that would result in a two-state solution, with the Palestinian Arabs being granted an independent state.

But with Hamas, which is committed to the destruction of Israel, now running the Palestinian Arab government, Mr. Blair accepted the new reality in the region, and hinted he would support Mr. Olmert’s disengagement plan if negotiations with the Palestinians proved to be impossible.

“You can only negotiate with people who accept your existence and stop violence,” said Mr. Blair at a joint press conference with Mr. Olmert.

“We can’t continue with what we have at the moment. We need a resolution or it slips back into chaos.”

Mr. Olmert professed himself delighted with the outcome of the talks.

“I feel very encouraged,” he said. “I am ready to make a genuine effort at negotiations based on the road map. But the conditions set by the road map are non-negotiable.”

Under those terms, the Israelis want the Palestinian Arabs to recognize Israel’s right to exist, renounce terrorism and disband their militias. The Israelis, for their part, are supposed to call a halt to all settlement activity in the West Bank.

Hamas terrorists have refused to accept these conditions, but Mr. Olmert said he was prepared to meet Mahmoud Abbas, the leader of the Palestinian Authority, to break the impasse.

But if “within a reasonable period” it was clear that a negotiated settlement was not possible, then Mr. Olmert would set about establishing Israel’s final borders unilaterally.