Organisers have said that at least 50,000 people marched through London on Sunday (29 November) in what was the UK's largest ever demonstration for action against climate change. In the run up to the UN Climate Conference in Paris starting Monday, activists have been marching in cities around the world.

Over 2,000 marches are said to have taken place since Friday.

Jenni Laiti, an artist and activist from the indigenous Sami community in northern Scandinavia, was part of a group of indigenous communities who led the march to highlight those already being effected by climate change. Laiti told IBTimes UK that "it was good to march together with our sisters and brothers... we are the movement and we have the power and we are the change."

Shadow Chancellor, John McDonnell attended the march, along with Labour leader Jeremy Corbyn. McDonnell told IBTimes UK, "These Paris talks could be absolutely fundamental to our tackling of climate change. We feel the British government has retreated on the commitments it gave a few years ago."

"[The government] increased our dependence on fossil fuels." When asked about the government's announcement that they will be increasing the amount of Energy Britain sourced from gas, McDonnell said "I don't think it's a long term solution, we should be concentrating on renewables."

jeremy corbyn climate march
Jeremy Corbyn and John McDonnell both attended Sunday\'s march Getty

Actress Emma Thompson, who has campaigned for years for action against climate change said she was marching because "I've got children and I'm very worried about the earth... what the summit in Paris represents to me is that for the first time 196 countries will coming together and that's because of popular movements... we can't do this except together."

Demonstrators gathered on Park Lane and marched through London, past Trafalgar Square, Downing Street and Parliament before finishing at Millbank where speakers from a number of organisations addressed the crowd.

All the major environmental organisations were represented - GreenPeace, WWF,, Friends of the Earth - alongside more local activists like Frack Free Lancashire, who were recently dealt a blow when the government announced that the final decision over fracking in Lancashire would be taken in Westminster instead of by the local council.

The COP21 talks in Paris have been described as the world's last real chance to avoid massive effects from climate change.

After the 13 November attacks in Paris, planned marches were cancelled in the French captial. A number of people gathered to create a human chain in Paris on Sunday but some protesters clashed with police and 100 people were arrested. Environmental organisation said that those involved in the clashes were "unaffliated with the climate movement."

COP21: What you need to know about the Paris climate change conference IBTimes UK