Protesters of the Extinction Rebellion clung to the Liberal Democrats' electric bus in London.
Jo Swinson, the party leader, was not on board when the activists arrived, but went to talk to them.
Lib Dems have been using an electric vehicle in the campaign.
Police called for bus in south London
Protesters clung to the bus
Police were called in and Swinson got his planned visit to a youth center in south London back on track.
Six people were at the location in south London and one of them, Pete McCall, was glued to the bus.
McCall said, "All parties are being targeted today."
Police arriving south of London
XR issued a statement saying, "The Extinction Rebellion is riding the field buses this morning and demanding that climate and ecological emergency be high on the agenda in this election."
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He added, "The protest, which is called the Bee-yond Policy," is being held to remind politicians of the irreplaceable loss of biodiversity that is a direct result of their poor and irresponsible policy. The activists wanted to implant the situation of bees and other pollinators totally in the minds of the next prime minister and remind them that they have the future of life in their hands.
Protesters of extinction rebellion on the bus
Protesters of extinction rebellion outside Lib Dem Pic election bus: extinction rebellion
"Our bee population is being threatened by extreme weather conditions and habitat destruction, bringing with it crop instability and food vulnerability."
Swinson told the protesters that it was "nice to meet them" and was pleased with the campaign work they were doing.
Protesters told her they considered it "paternalistic" to call the campaign, and said they were in "active rebellion against the government."
She responded by saying that she had participated in an XR protest and said the Lib Dems were committed to reaching net carbon zero by 2045.
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