A London Underground driver announced "Free Palestine" to passengers, who joined in the chant and clapped.
The City of London said that "the mayor is committed to ensuring the safety and security of all Londoners when they use public transportation. Anyone who breaks the law or incites violence and hatred will be taken action against."
The London police said that they are investigating the case: "We are aware of photographs circulating on social media that show chants being led by a train driver in London."
The subway also said that they are looking into the case: "We are committed to providing a safe network for everyone and want to make it clear that London is open to everyone."
"We are aware of the photographs being circulated on social media indicating that political comments may be made by one of our YouTubers. We are working to examine the photographs and ensure that the case is investigated urgently."