Keir Starmer has said said the fighting in Gaza “must stop now” and told Israel not to launch an offensive in the city of Rafah.
Speaking to the Labour Party’s Scottish conference on Sunday, Starmer called for a “ceasefire that lasts”.
It comes ahead of a Commons vote on Wednesday tabled by the SNP which will ask MPs to back an immediate ceasefire.
Starmer suffered a significant rebellion in November when 56 Labour MPs defied his instructions not to support a similar motion.
The Labour leadership’s strong support for Israel’s reaction to the October 7 massacre by Hamas has exposed deep divisions within the party.
Starmer said today: “I have just returned from the Munich Security Conference.
“Every conversation I had came back to the situation in Israel and Gaza. And the question of what we can do, practically. To deliver what we all want to see, now.
“A return of all the hostages taken on 7 October. An end to the killing of innocent Palestinians. A huge scaling up of humanitarian relief. And an end to the fighting.
“Not just now, not just for a pause. But permanently. A ceasefire that lasts. That is what must happen now. The fighting must stop now.”
He added: “Any ceasefire cannot be one-sided. It must stop all acts of violence, on both sides, it must lead to a genuine peace process.
“The offensive threatened on Rafah – a place where 1.5 million people are now cramped together in unimaginable conditions with nowhere else for them to go – this cannot become a new theatre of war. That offensive cannot happen.”
Earlier on Sunday, David Lammy, the shadow foreign secretary, said Labour would consider backing this week’s SNP motion.
But he told the BBC’s Sunday with Laura Kuenssberg programme a vote in the British parliament “will not bring about a ceasefire” between Israel and Hamas.
And Owen Thompson, the SNP chief whip in Westminster, said it was “entirely untrue” that Labour had been in touch about the vote.