British police on Sunday arrested six people who are members of the Palestine Action protest group as part of an investigation into an alleged plot to disrupt the London Stock Exchange.
The police alleged the activists had planned to target the LSE on Monday morning in an attempt to prevent the building opening for trading.
In a statement, London's Metropolitan Police said three people were arrested in the northern English city of Liverpool, two in London, and one in the south coast city of Brighton.
"These are significant arrests. We believe this group was ready to carry out a disruptive and damaging stunt which could have had serious implications had it been carried out successfully," said Detective Superintendent Sian Thomas.
The police said all six activists remained in custody.