Israeli prime minister Binyamin Netanyahu is set to visit London on Wednesday of next week to meet David Cameron.
The Palestine Solidarity Campaign (PSC) has called for people to join a protest outside Downing Street to greet him.
Netanyahu oversaw the Israeli assault on the Gaza Strip last year. It killed more than 2,000 Palestinians – and the British government backed it.
Cameron has blamed Palestinians for the slaughter. Earlier this year he said, “Israel uses its weapons to defend its people and Hamas uses its people to defend its weapons”.
And the British government approved the sale of £7 million worth of arms in the six months leading up to the assault.
The sales included parts for drones and combat jets, as well as ammunition.
The government briefly suspended arms export licences to Israel during the assault. But Tory business secretary Sajid Javid lifted it in July.
More than 90,000 people have signed an online petition calling for Netanyahu to be arrested as a war criminal when he arrives in Britain.
And hundreds of thousands of people joined Palestine solidarity protests last year, including a march of more than 150,000 people in London.
The protest next week will show that opposition to Israel hasn’t gone away.
PSC director Sarah Colborne said, “We should all be asking David Cameron why he and his government are welcoming a war criminal to the UK.
“This protest will do exactly that, and it will also make it clear to Netanyahu that he’s not welcome here.”