EDIT, 1 July, 11am:
There's a new Anti-Brexit protest taking place this Saturday, 2 July, marching from Park Lane to Parliament Square
EDIT, 28 June, 3pm:
We've received details of a new protest, taking place at Trafalgar Square tonight, Tuesday 28 June, between 5pm and 9pm.
A second post-Brexit march is planned for central London, on Saturday 9 July.
The first rally, organised for 28 June, has been cancelled due to the huge numbers of people signing up.
The Stand Together: London Event announced the cancellation on the Facebook event page, saying: "It started with the idea of bringing 20 friends together in London Fields park in East London, and now we have over 50,000 people who want to stand together in London.
"We've tried all we can to ensure this could go ahead. However logistically it’s not possible to ensure a safe event.
"Trafalgar Square can hold 10,000 people - and that’s with security barriers, stewards, road closures, and a full contingency plan. Considering the speed with which this event has picked up, arranging everything required in time is simply not possible.
Given this, with a heavy heart, it's too dangerous for the attendees for the event to go ahead."
There are few clues on the new Facebook event, called Anti Brexit March (which currently has 3,400 people listed as attending, and another 10,000 interested) as to whether more concrete contingency plans have been made.
Details are sketchy. The second rally's location is given as Big Ben, so Parliament Square, and the suggested times are from noon to 8pm on Saturday 9 July.
So far the page, created by Londoner Kieran MacDermott, simply says "To replace deleted event. More details to follow."
There are similar post-Brexit #StandTogether events planned across the country, in Oxford, Manchester, Cardiff, Liverpool, Cambridge and Leicester.