Users completing the survey received the following message:

“Would you be willing to participate in a study of people’s internet usage. This involves downloading a piece of software onto your computer to track which websites you visit. It will not slow down your machine.”

YouGov claims no software was offered and instead came from the survey operator on behalf of a different client.

“YouGov is constantly looking for ways to improve the survey experience for its panellists and carries out regular screening on a whole range of activities,” the survey operator said. “The questions on this occasion were simply part of  a standard screening exercise to measure feasibility for such a project – we do not currently have a commissioned study of this nature.  At any given time we conduct studies with the agreed participation of our panellists that provide us information that allow us to improve our services.”

It is currently unclear precisely what the point of the offer to download what amounts to spyware was.