Marie Curie has said it is investigating how its advertisements have appeared on extremist videos on YouTube.
The Times newspaper has today published a report of an investigation that found advertisements for numerous big-name brands, including Mercedes-Benz, Waitrose and Argos, were showing up on videos posted by terrorist or extremist groups such as Islamic State and the pro-Nazi faction Combat 18.
None of the brands were aware that their adverts were appearing on the videos, which The Times said could be generating tens of thousands of pounds a month for extremists.
An advertisement appearing alongside a YouTube video earns whoever posts the clip a share of any advertising revenue, which can typically work out at between about £4 and £6.40 for every 1,000 views, the newspaper said.
An advertisement inviting people to volunteer for Marie Curie, which supports people with terminal illness and their families, appeared as a pop-up on a video posted by Combat 18, The Times reported.
A spokeswoman for Marie Curie thanked The Times for bringing the matter to its attention.
"We are extremely concerned that our advertising has appeared in this way," she said in a statement.
"We are investigating how this has happened and will take whatever further steps are necessary to ensure this does not happen again."