Four women from the Occupy movement have chained themselves to the pulpit in London's St Paul's Cathedral, a church official said.
The Very Reverend Dr David Ison, Dean of St Paul's, said he was taking an evening prayer service when "four young women dressed in white" chained themselves to the structure.
Four Occupy activists staged a "mic check" during Evensong and then chained themselves to the pulpit. They were not planning to leave, an Occupy spokesman said.
Officers are currently allowing the protest to continue and were no longer inside the cathedral, a spokesman for City of London police said.
Staff at the cathedral informed police they were happy for the activists to remain and so police left the building but maintained a presence outside to police the protest there, the spokesman said.
Protesters have unfurled a large banner reading "throw the money changers out of the temple" on the cathedral steps. The action came as the group marks the anniversary of its now-dismantled protest camp outside the cathedral.
The Dean said he and a member of Occupy Faith, the group's religious wing, were leading a prayer when the women came up and started shouting.
"It will be a long cold night if they want to stay there," he said. "I don't know what they want to do. I'm just sorry they have decided to do this, which makes it hard for members of Occupy Faith, who have been working together with us on something which is respectful."
Occupy London released a statement which said they were collaborating with Christianity Uncut to call for the leadership of St Paul's to "stop sitting on the fence and join the fight against rising inequality in the UK and beyond."
Last year hundreds of people set up camp outside St Paul's on October 15 after they were prevented from entering nearby Paternoster Square, where the London Stock Exchange is located, and remained there for four months. The church, caught in a conflict between the demonstrators and London's finance industry, changed its stance on the camp several times.