Chief Rabbi Lord Sacks has given the government a stern warning about peace in the Middle East, marking the first time he has spoken about Israel in the House of Lords.

The comments came during a debate in Parliament yesterday about the Middle East peace process.

Controversial Lib Dem peer Jenny Tonge, who was sacked as the party's health spokesman last year after suggesting that Israel had harvested organs from Haiti earthquake victims, led the debate.

During her question about the government's progress in the Middle East peace process, Baroness Tonge said Israel had broken international law since 1948, when "it decided that the Palestinians would pay the price of the Holocaust".

She accused Israeli snipers of targeting children as they collect gravel and said Israel had an "apartheid-like regime". She said that Israel's fear of Hamas is based on "the old Hamas charter, which is a relic".

In response, Lord Sacks, who was given a life peerage in 2009, said peace meant "a state in which I recognise your right to exist, and you recognise mine".

He said: "How then can we be speaking about peace when Hamas remains committed as a matter of principle to the elimination of the state of Israel, when it engages in missile attacks against innocent civilians, and uses its own innocent civilians as human shields; when it propagates some of the most vicious antisemitic myths ever to have inflamed the hatred and anaesthetised the conscience of human beings, and two days ago praised Osama bin Laden as a holy warrior; and when it refuses to agree to the fundamental principles laid down by the Quartet, not least of which is the recognition of Israel's right to exist?

"Until Hamas undergoes fundamental change, there may be a process, but there will not be peace. Peace is more than a resting place on the road to war. I cannot make peace with one who denies my right to exist.

"I urge the government to be resolute in its insistence that the path to peace in the Middle East must begin with the unequivocal recognition of the state of Israel's right to be."

Baroness Verma, spokeswoman for the Department for International Development, said: "Hamas must renounce violence, recognise Israel and accept previously signed agreements.

"Britain hopes that the announcement of reconciliation between Fatah and Hamas will lead to the formation of a government that rejects violence and pursue a negotiated peace, and we will judge a future Palestinian government by their actions and readiness to work for peace."