Dr Mike Nutt spends every Thursday afternoon sitting outside the main Barclays branch on Pinstone Street.
He wants to highlight the role of banks in the funding and underwriting of global fossil fuel industries and says most customers are unaware of the link between climate change and fossil fuel burning.
The grandfather of two says he has particularly singled out Barclays as a British owned bank and the largest funder of oil, coal and gas projects of all European banks.
He said Rainforest Action Network stated Barclays has funded these industries by $145,000,000,000 since the Paris Climate agreement in 2016.
“As a medical doctor I am aware of research findings which shockingly show that premature deaths globally from air pollution each year in the past decade number in excess of eight million people. This is from a combination of respiratory and cardiovascular diseases.
“A major contributor to this excess is the burning of fossil fuels, particularly motor vehicle exhaust fumes.
“The world faces a dire situation due to global warming and weather change, with the droughts, floods and fires recently seen all, predicted to worsen over the coming years
“A motion at Barclays’ AGM this May to totally align Barclays finances in accord with the 2016 Paris agreement and ban any new funding for fossil fuel extraction and related projects was voted against.
“If Barclays took a lead it would send a great message out to all other banks.”
A Barclays spokesman said: “We have made a commitment to align our entire financing portfolio to the goals of the Paris Agreement, with specific targets and transparent reporting, on the way to achieving our ambition to be a net zero bank by 2050.
“We believe that Barclays can make a real contribution to tackling climate change and help accelerate the transition to a low-carbon economy.”
Dr Nutt has been supported by the drama group Act Now, which has also protested outside Lloyds, NatWest and Santander.