More than 10,000 Londoners are going to march from Marble Arch to Downing Street as part of a national day of action to urge the government to accept more refugees into the UK.
The march will start at 12pm, with protesters being told to meet at an assembly point in Marble Arch, before walking towards Pall Mall and down Whitehall to Downing Street.
The national day of action, called by a coalition including Stand up to Racism, Stop the War Coalition and Migrant Rights Network War on Want, will also see protests take place in Scotland, Wales and the North.
More than 100,000 people have said they might attend, with 20,000 having confirmed, however organisers are being more modest with their estimates of the number that will actually turn up on the day.
Sabby Dhalu, who represents Stand Up To Racism, told City A.M: "There is a huge level of support, the largest amount the movement has galvanised in at least the last two decades."
That volume of people will of course have a knock-on effect with traffic and other forms of transport.
Marble Arch Tube station is expected to be extremely busy, so protesters have been advised to use Hyde Park Tube station.
The UK's response is widely seen as not going far enough however: Germany, for example, has said it will take 500,000 refugees a year for the next few years.
The organisers want to see the UK share more of the burden.
"It is extremely irresponsible for the UK to leave the responsibility to other countries. A few thousand does not match up to the scale of the crisis, especially when you look at countries such as Turkey and Germany. There is no reason Britain can't take a lead on this important issue," Dhalu said.