Demonstrators waved flags, carried placards and let off red smoke bombs as they marched on parliament on Sunday afternoon.
The rally, which started at the BBC’s Broadcasting House before heading to Westminster, follows similar protests in Paris and Berlin on Saturday.
It comes five days after Turkey launched an assault across its border with Syria in what it claims is a bid to establish a 30km “safe zone” inside its neighbouring country.
Some 200 people have since been killed in the resulting fighting – many Kurdish civilians who had helped to establish a rare and widely-praised corridor of stability in the region.
Some 130,000 refugees have also been created, the UN has said, mostly Kurds fleeing the bombarded towns of Ras al-Ain and Tell Abia.
Ankara launched the action after US President Donald Trump withdrew American troops from the area – an unexpected move widely condemned by both domestic supporters and international allies alike who said it was a betrayal one of the West’s most trusted regional allies, the Kurds.
Speaking at the London demonstration, Niaz Maarof, a 41 a driver from London, said he was furious with what was happening.
He told the PA news agency: “This is a demonstration showing against Erdogan and Turkey attacking the Kurdish in Rojava after almost 10 years that we have been fighting against ISIS.
“They liberated the area, they are running a democratic government and now Turkey, with the green light from America, is attacking the area.”
He added: “The world does owe the Kurdish now for what they did in Syria. If you really mean it, the British should stop selling Turkey weapons, because last year Theresa May gave them planes and now they are using them against us.
“The whole world is watching and no-one is saying anything.
“We, the Kurdish, are upset, not only with Turkey but with most of the world, because we are not being helped.”