TURKEY must be treated as a pariah state, protesters in London demanded today, as thousands branded Turkish President Recep Tayyip Erdogan a war criminal.

The calls came as Britain’s Kurds and their allies turned central London into a sea of red, yellow and green for the second successive weekend.

They called for people to “Rise up for Rojava” — the semi-autonomous Kurdish enclave of northern Syria — and defend it from invasion by Turkey and its jihadist proxies.

Families of British volunteers who died fighting for the Kurds led the procession from BBC headquarters in Portland Place to Parliament Square.

Dirk Campbell, whose daughter Anna Campbell was killed in a Turkish airstrike in Afrin last year, announced that he had launched a legal case against Turkish and British authorities.

They have refused to allow him safe passage to collect his daughter’s body despite providing co-ordinates of where she fell.

Protesters called for Turkey to be isolated as a pariah state in the same way that apartheid South Africa was in the 1980s, as they accused Mr Erdogan of war crimes.

Rosa Gilbert from the Kurdistan Solidarity Campaign said: “While international institutions are sitting idly by, or even enabling the invasion, Turkey’s war crimes are no longer going unnoticed and no matter how much propaganda gloss is put on it, ordinary people around the world won’t be duped.”

Mr Erdogan has faced an international backlash over his invasion.

Public opinion has turned against him after images emerged showing children burnt by what experts believe is white phosphorus, an incendiary weapon which is banned for use on civilian populations.

While the UN said it would look into these claims, Kurds remain sceptical.

Saban Disli, the Turkish official who announced he would investigate the allegations, has donated €30,000 [£25,800] to the Organisation for the Prohibition of Chemical Weapons.

Labour MEP for North West England Julie Ward, who has headed up a women’s delegation to Rojava, told those gathered that Britain has a duty to stand against Turkey’s war.

“The people who died in Syria fighting against Isis were doing it for us and the whole of humanity,” she said.

“It is absolutely shameful that this government is selling weapons to Turkey.

“We know that those arms are killing women, are killing children and are killing innocent civilians. And we will not stand for that.”

Former human rights barrister Margaret Owen, who joined Kurdish hunger strikers this year to demand an end to the isolation of jailed Kurdistan Workers’ Party (PKK) leader Abdullah Ocalan, called for a judicial review into Britain’s continuing arms trade with Turkey.

And in a message read out to the crowds, British volunteer Dani Ellis explained how she was part of relief efforts that saw 25 vehicles through enemy territory to break the siege of Sere Kaniye, the scene of fierce fighting and resistance from Kurdish fighters.

She said that, as the convoy returned with the wounded, they were met by crowds who raised their finger in the air — a gesture associated with jihadists.

“If it were not for their Turkish uniforms, Turkish weapons and Turkish arm patches, these men would have been indistinguishable from the very Isis and al-Qaida militants the Kurds and their friends sacrificed so much for to defeat over the last seven years.”

She said: “While some of us fight here on the ground with our weapons it is just as important that our friends abroad fight this Turkish aggression with words and with direct action.

“Because this is not just a fight for dignity, for democracy and for humanity.

“It is a war that all parts of society must come together to wage, not just the soldier on the battlefield.”