Rishi Sunak and Benjamin Netanyahu are giving a news conference in Jerusalem.
Mr Netanyahu says Hamas “are the new Nazis and the new ISIS” and this current war in the Middle East is a “battle for the free world”.
“We have two forces here. One is an act of evil led by Iran which want to bring the Middle East back to the Middle Ages,” he says.
“The other force is a force of progress and humanity.”
The Israeli leader says this is his country’s “darkest hour” and “it is the world’s darkest hour”.
“We want to stand together and we want to win,” he adds.
He says to Mr Sunak that Israel needs the UK’s support and “unity across the board”, adding that Hamas “are the worst monsters on the planet”.
Mr Sunak in response says he “supports Israel’s right to defend itself in line with international law” and “go after Hamas”.
“I know you are taking every precaution to avoid harming civilians in direct contract to the terrorists of Hamas which seek to put civilians in harms way,” he tells Mr Netanyahu.
“We recognise the Palestinian people are victims of Hamas too,” he says, and adds he welcomes Israel’s decision to open humanitarian routes into Gaza.
He adds: “You described this as Israel’s darkest hour, well then I am proud to stand here with you in Israel’s darkest hour as your friend. We will stand with you in solidarity and your people and we also want you to win.”
3,785 Palestinians killed, say Gaza officials
At least 3,785 Palestinians have been killed in Israeli strikes on Gaza, the territory’s health ministry has said.
This means the death toll has increased by 300 people since they last released figures.
Earlier today the ministry said another 12,065 were injured, with 70% of casualties being children, women and the elderly.