Hong Kong protest outside Chinese embassy in London
Demonstrators have gathered outside the Chinese embassy in London to support pro-democracy protesters in Hong Kong.
Organisers of the London protest said 3,000 people had gathered to show people in Hong Kong "they are not alone".
Many carried umbrellas, the symbol of protests in the former British colony.
Thousands of people have taken to the streets in Hong Kong after China said it would vet candidates for a leadership election in 2017.
"We are out to tell people in Hong Kong you are not alone. There are many people standing together across the world," said Desmond Sham, one of the organisers.
The PhD student from the Hong Kong Overseas Alliance added: "We are just one of the actions of global solidarity."
Student demonstrators in Hong Kong have vowed to step up their mass pro-democracy protests if Chief Executive CY Leung does not resign by Thursday.
Protests continued on the streets on Wednesday - China's national day - with thousands remaining camped out at the main protest sites as evening fell.
Ex-Governor Chris Patten accused China of breaching commitments it made to Hong Kong before taking over sovereignty from the UK in 1997.
At the scene: Nick Eardley, BBC News
They may have been 6,000 miles apart, but Wednesday's protest in London shared many of the characteristics of the movement in Hong Kong.
Many of the demonstrators outside the Chinese embassy were young and recorded the scenes on their mobile phones.
Many held aloft yellow umbrellas, the powerful symbol that has earned the movement in the former colony the nickname the umbrella revolution. Others carried placards and banners demanding "Democracy by 2017" - the year the next chief executive is due to be elected.
Among those gathered were expats from Hong Kong and others here studying. One protester told stories of family members who were on the streets at home. Another said this was her last night in London before leaving for home to join the protesters.
All spoke passionately about the prospects for democracy in the former British colony and their hopes for the future. And they were clear in their intention - to show people in Hong Kong that they had international support.
Meanwhile, in London, organisers said the turnout had "exceeded expectations". Portland Place has been partly closed by the protest.
Ellen Or, 49, who studies in London but is returning to Hong Kong on Thursday to join the protests there, said she was demonstrating "for the future of Hong Kong".
She added: "This will give support to them and let them know they are not alone."
Bill Hung, 30, is also from the former colony. He said his brother had been involved in the protests in Hong Kong.
"The world is watching. The UK is behind Hong Kong, universal suffrage and real democracy," he added.
Yao Liao, originally from Taiwan but also living in London, said: "I want them to know people in Taiwan support them."