Protesters shouted "shame on you" at the Duke of Cambridge as he entered Westminster Abbey for a service to mark 50 years of the UK's nuclear deterrent.
Activists from the Campaign for Nuclear Disarmament (CND), who were across the road from the abbey as Prince William's car pulled up outside, booed and chanted, condemning the duke's attendance.
The group, along with their placards and banners which read "Blessed be the bomb makers" and "Abolish war", also staged a "die-in", where people lay on the ground pretending to be dead, to commemorate victims of nuclear war.
CND's general secretary Kate Hudson, who was at the protest, said: "I think it's absolutely inappropriate that thanks should be given for nuclear weapons and we're not alone on this."
She added: "The die-in will be symbolic of those people who have been killed in nuclear war and a sign of what would happen in the event of nuclear war."
At the same time, a counter-service was held by the Christian branch of the group.
The Reverend Matthew Harbage, from St Marks church in Regent's Park, central London, said: "We're here because the Abbey is holding a service to celebrate the nuclear deterrents, we believe this is wrong based on our theological principle.
"My reaction to this service was one of surprise and deep disappointment.
"I'm really keen to understand why this particular abbey has decided to host this service and I want to bring people on side to recognise the contradiction between Jesus Christ, who gave his life for others, and nuclear weapons, which can only be used for killing."
