British Prime Minister Rishi Sunak emphasised the need to protect "democratic values" in a Downing Street meeting on Friday with his under-fire Israeli counterpart Benjamin Netanyahu, the UK leader's office said.
Netanyahu landed in London after weeks of escalating protests in Israel over his government's judicial reform programme, which would increase politicians' power over the courts and critics argue is a threat to democracy and Palestinians.
While some of Israel's allies abroad, including the leaders in the United States and Germany, have raised concerns about the controversial overhaul, the UK has remained silent on the subject.
Sunak "stressed the importance of upholding the democratic values that underpin our relationship, including in the proposed judicial reforms in Israel", a Downing Street spokesperson said in a summary of the two leaders' meeting.
Hundreds of protesters, many holding Israeli flags and placards critical of Netanyahu, rallied outside the gates to the street to heckle his arrival.
Some shouted "shame" in Hebrew as Sunak greeted the country's veteran leader at the door of 10 Downing Street.
They erected the letters of the word "democracy" on nearby Whitehall, while wielding signs accusing Netanyahu of dragging Israel towards "dictatorship".
"It's important to be here because maybe at some point they won't have the right to protest in Israel," Dana Drori, a mother-of-two in her 30s, told AFP at the protest, alongside her young daughters.
"It's anger, it's sadness," she said of her emotions. "It's just hard to believe it's becoming a dictatorship."
In a televised address hours before departing for London, Netanyahu pledged to restore unity within his increasingly fractured country, but gave little away about how he would do that while still pursuing the reforms.
The UK government has released few details about Netanyahu's two-day visit.
It comes days after the two countries signed a wide-ranging "2030 roadmap" agreement, which London said "will drive our bilateral relationship forward" as it looks to strike a post-Brexit free trade deal.
During their meeting, the two leaders discussed "the UK and Israel's significant concern about Iran's destabilising activity" and the risk of "nuclear proliferation" posed by its atomic programme, Downing Street said.
They also talked about the war in Ukraine and developments in the Middle East, its statement noted.
Sunak "expressed his solidarity with Israel in the face of terrorist attacks in recent months" while noting unspecified actions risked "undermining efforts" towards a two-state solution to the Palestine-Israel conflict, it added.
"He encouraged all efforts to de-escalate, particularly ahead of the upcoming religious holidays."
It comes amid a deadly start to 2023 for Palestinians, with 90 killed so far at the hands of Israeli forces and settlers.
Netanyahu also met hardline Home Secretary Suella Braverman – who has herself faced stinging criticism over controversial UK plans to deter asylum-seekers.
They met to "discuss shared security interests and joint efforts in tackling state threats", Braverman tweeted.
Protests by pro-Palestinian groups and others opposed to Israel's judicial reforms were held near Downing Street, including women's rights campaigners dressed as characters from dystopian drama The Handmaid's Tale.
"As Palestinians from the diaspora we see ourselves at the front line of the fight for a free Palestine and when Netanyahu comes to visit in our backyard, we have to protest it," said one 24-year-old protester, who gave her name only as Yasmine.