The London demonstration was called by a wide range of NGOs and campaigns including Stand Up To Racism.
Jess, a doctor from Brighton, brought her children "to show that we should open the borders and accept people."
IT support worker Alan heard about it through an Amnesty International email.
"I just think the government's stance on refugees is immoral," he said. "It's such a huge humanitarian crisis and they are just ignoring it."
Many marchers were returning a year after first protesting following the death of three year old Syrian Kurdish refugee Alan Kurdi. Bournemouth students Summer and Katie were horrified at how little has been done since. "I've been really disappointed at how shit the government has been," said Katie. "It's even more important to demonstrate given the amount of anti-refugee and anti-immigration rhetoric."
Summer added, "You get politicians, especially Conservatives, saying oh it's a tragedy and we're doing so much about it but they're not doing a lot at all."
The protest was called partly to pressure two summits on refugees of world leaders on Monday and Tuesday. But campaigners are finding resistance from every level of the state.
Rose and Urvashi from north London were part of a campaign lobbying Labour-run Haringey council to take in four Syrian families by Christmas.
"It's not a lot, but it's a start," said Rose. "Haringey has a lot of capacity for refugees but the council refuses to make any commitment. It's because of such refusals that the number of refugees here is so small."
Urvashi added, "When we go out with our petition everyone is shocked the council won't take any refugees. This is something everyone wants - except the council."
Placards ranged from many showing butterflies and Paddington Bear to symbolise migration to defiant slogans like "open the borders" and "no-one is illegal".
Doctors Without Borders held up photos of the camps, boats and fences our rulers want to hide. Amnesty activists' placards were covered in signatures from supporters in their area.
Outside Downing Street protesters chanting "Hey hey Theresa May, how many kids did you kill today?"
Some drew attention to the role of Britain's rulers' wars in creating the refugee crisis.
Kat from Campaign Against the Arms Trade held a banner saying "refugees welcome, arms dealers not". She explained, "Big arms companies are fuelling wars - and they're often the same companies profiting from enforcing Europe's borders."
The march was smaller than last year's - addressed by newly elected Labour leader Jeremy Corbyn, in a week when even the most rabidly anti-migrant papers had baby Alan's picture on the front - but its size testified to the resilience of support for refugees.
However a tiny turnout from trade unions and the Labour Party underlined how much remains to be done.
It comes days after the latest death at Britain's border in Calais, of a teenage boy trying to join his family in Britain.
At a closing rally, 7 year old Ahmed who nearly suffocated in the back of a lorry escaping Calais last year, spoke through a translator. "Thank you all for trying to make a difference," he said. "I am one of the lucky few, but I still feel for all the people stuck in the jungle and around the world."
Labour's Lord Alf Dubs hailed the "fantastic" demonstration and urged campaigners to continue. "There's only one thing that's shifting this government and that's the force of public opinion, and that means you," he said.
Dubs, who came to Britain as a child refugee himself, will be speaking at the Stand Up To Racism conference on Saturday 8 October to build the campaign to bring refugee children to Britain.
Anti-racist campaign is launched in Scotland
There was standing room only at Stand Up To Racism’s (SUTR) Scotland launch conference in Glasgow last Saturday.
The speakers and the new steering committee reflected a wide range of support.
These included leading figures from the Scottish TUC, EIS union, Sheku Bayoh justice campaign, Glasgow Campaign to Welcome Refugees, Unite Against Fascism and others.
Labour and Scottish National Party MEPs and people from the Green Party and Solidarity also took part.
So did “Glasgow Girl” refugee campaigner Amal Azzudin and human rights lawyer Aamer Anwar.
There was a very serious discussion of the challenges anti-racists face in the wake of recent violent attacks (see pages 10&11).
We cannot be complacent in Scotland.
There was shock that Nazi group National Action had collected for exclusively white homeless people in Glasgow—and that police will allow them to continue.
Activists pledged to keep up the annual SUTR demonstrations on United Nations anti-racism day in March.
They vowed to build a Scotland-wide campaign against the building of new detention facilities to replace Dungavel.
The next step will be building SUTR meetings locally including on housing estates and in colleges.