LONDON (AP) — Britain’s signals intelligence division is stealing screenshots from hundreds of thousands of innocent Yahoo users’ webcam videos, according to the Guardian newspaper, which also reported that the years-long operation has swept up a huge haul of intimate photographs.

The newspaper said GCHQ has been scooping up the sensitive images by intercepting video chats such as the kind offered by Yahoo Messenger, an effort codenamed OPTIC NERVE. It’s not clear how many Yahoo users were spied on in this way. The Guardian said that in one six-month period in 2008, GCHQ intercepted the video communications of 1.8 million users, but it’s possible that the program, which the Guardian says was still active in 2012, has either grown or shrunk in scope since then.