Theresa May has outlined her view of Britain's relationship with Israel following the Brexit vote.
She praised the economic ties between the countries, urging greater cooperation on healthcare, cyber security and counter-terrorism efforts.
In her first speech to Conservative Friends of Israel as Prime Minister, Mrs May also confirmed the government would support the International Holocaust Remembrance Alliance's definition of antisemitism.
Mrs May told the audience of more than 800 - CFI's biggest ever lunch - that the Balfour declaration had been "one of the most important letters in history". She pledged the government would celebrate next year's centenary anniversary "with pride".
"Our two countries have a great deal in common," the Prime Minister said. But she said there was "more to do" and attacked Israeli settlements in the West Bank as "illegal. They are not conducive to peace. It must stop".
Mrs May attacked Labour's approach to tackling Jew-hatred. She cited Tom Watson, the party's deputy leader, singing Am Yisrael Chai at Labour Friends of Israel's annual lunch a fortnight ago. She said it had been "karaoke" and could not make up for the party "turning a blind eye to antisemitism".
The Prime Minister received a prolonged standing ovation at the Westminster lunch, which was attended by more than 200 Tory parliamentarians including cabinet ministers, former ministers and backbenchers.
Mark Regev, Israel's ambassador to Britain, addressed the audience and CFI chairman Sir Eric Pickles said ministers and officials from countries including Cyprus, Australia and India were attending.
CFI's Andrew Heller warned that many MPs faced "intimidation" from anti-Israel activists in their constituencies and urged supporters to help bear the £2,500 per person cost of taking politicians on delegations to Israel.