The activists were also demonstrating against the unethical treatment of garment workers by big name high street brands.
Dozens of activists stood peacefully in front of Topshop, Zara, H&M and Urban Outfitters with placards featuring slogans such as 'People & Planet over Profit, Topshop, Primark, Zara, Urban Outfitters PAYUP' and '#TellTheTruth - The Fashion Industry's Carbon Impact is Larger than Aviation.'
Fashion is a highly polluting industry which generates waste and pollutants throughout the lifecycle of products – from the manufacture of fabric to the disposal of garments.
In 2015, the total greenhouse gas emissions from textiles production was estimated to be 1.2 billion tonnes of CO2 equivalent. That's more than the greenhouse gas emissions of all international flights and maritime shipping combined.
Yet despite the fashion industry's damaging impact, fast fashion companies have built business models that encourage people to buy and dispose of new items every month. Last year the industry produced 140 billion new garments.
The ruthless approach of fast fashion brands has been further exposed by the Covid-19 crisis.
Several UK high street names cancelled or suspended £2.4bn worth of orders during the pandemic, causing more than a million Bangladeshi garment workers to be sent home without pay or lose their jobs.
Hermione Berendt, a spokesperson for Extinction Rebellion,said:
"Black, Indigenous and People Of Colour living in the global south are already the most vulnerable to the impacts of climate change, which are fuelled partly by fast fashion.
"Covid-19 has shown that Black, Indigenous and People of Colour are shamelessly exploited by the fast fashion industry too, with big name brand putting profit before people and planet once again.
"It's outrageous that these brands, some of whom have outlets in Churchill Square, left their garments workers without a livelihood during a global health pandemic.
"This is a window into the future. The vulnerability of garment workers in the global south will only get worse as the impacts of the climate and ecological emergency ramp up.
"Now the shops are back open, will the big brands go back to business as usual or will they come together to build back a better fashion industry?"
The protest was part of a global action with Extinction Rebellion Fashion Action, Animal Rebellion and Extinction Rebellion Fashion Action Netherlands.