Green activists have launched a new bid to bring London to a standstill over the busy Christmas season in their latest protest against fossil fuels.
Just Stop Oil, a spin-off from Extinction Rebellion well-known for vandalising famous artworks, began 17 days of roadblock protests on Monday.
The first reported incident came from The Strand, a main road running along the north bank of the Thames in central London, where around a dozen people walked slowly down the middle of the street holding banners.
Another protest took place in Shepherd's Bush, a busy junction of several major routes through west London.
A briefing by the group tells activists to strike during rush hour and "march as slowly as possible from key roundabouts in multiple teams and timed phases."
It also advises participants to frequently change location to make it difficult for police to counter them, or to "lock on" to the road surface or fixed objects with superglue and bicycle D-locks.
The protests will coincide with a strike by bus drivers in the capital, potentially forcing more Londoners to drive to work and further raising tensions.
But the Metropolitan Police urged drivers not to take the law into their own hands, as others have done by dragging protesters off the road.
"I completely understand the frustration and anger felt by the public who are seriously disrupted by a relatively small number of protesters and their deliberate tactics," said Commander Karen Findlay. But she pledged that "where activists cross the line into criminality, the Met will provide a proportionate policing response."
Police have been criticised for failing to stop previous protests that blocked bridges and tunnels, as well as motorways around the capital.
Prime Minister Rishi Sunak was set to meet senior officers later on Monday to ask if they needed additional powers to deal with the disruption.
The Met arrested 755 Just Stop Oil activists at a variety of protests in October and November.