Protesters have set up a sofa and are serving tea in a blockade outside a busy bank branch in Piccadilly Circus.
Campaigners from Friends of the Earth stood outside the glass windows of the central London Barclays branch and held signs and teapots as they protested against fracking.
The protest is a bid to stop council-approved plans for company Third Energy, which is largely owned by Barclays, to begin fracking in Ryedale, north Yorkshire.
The protesters, including some who dressed up in high-vis workmen’s outfits and hard hats, held signs which read “keep Ryedale rural, NO fracking”. Campaigners also gave out biscuits imprinted with anti-fracking messages.
Other signs read: “Don’t keep calm and stop fracking.”
The sit-in, at the busy London intersection, was noticed by many passers-by, some of whom shared what they had seen on social meida.
Stephen Rockman said on Twitter: “Cops, protesters, Barclays & tourists…hard tell who’s more bemused.”
Piccadilly Circus Barclays Bank has been rather invaded by anti-fracking people.
Well, shouty banner — waving at the entrance, anyhow The protest was organised 
by Frack Off London and Divest London.
The sit-in began at 11.45am and saw Ryedale resident Nicky Hollins and her 13-year-old daughter sit in a mock-up of their living room.
Photos from the crowded scene also showed officers from the Met Police standing by.
The protest is part of a week of similar action, with sit-ins also held outside branches in Cambridge, Manchester and Hastings.
North Yorkshire County Council gave permission to Third Energy to frack in May this year.
The Standard has contacted Barclays for comment.