A Jeremy Corbyn support rally to be held tonight by left-wing group Momentum has been cancelled due to "overwhelming demand".
The group was set to hold a rally tonight in Congress House, but says the event will now be postponed.
It said: "Due to overwhelming demand for tonight’s meeting in Congress House we have unfortunately had to postpone.
"We apologise to members that were looking forward to attending in order to hear how we can continue to build our movement and work towards a Corbyn-led Labour government.
"Local groups across the country will be running similar events over the coming weeks and communicating details via email and social media.
"Thanks for your support."
Corbyn has come under pressure from MPs within his own party to stand down due to feeble leadership during the EU referendum campaign and fears that he would suffer a catastrophic defeat in any general election.
However, those in Corbyn's wing say he is a victim of factions in the party making moves against him, that he will not stand down given the mandate he was given from voters, and would stand in any future Labour leadership election.
Yesterday thousands of people gathered in central London in support of Corbyn.
Momentum was set up following Corbyn's Labour leadership election last year to garner enthusiasm in the grass roots for the left-wing of the party.
Momentum says it "exists to build on the energy and enthusiasm from the Jeremy Corbyn for Labour Leader campaign, to increase participatory democracy, solidarity, and grassroots power and help Labour become the transformative governing party of the 21st century", but has been called militant by critics.