Facebook has started the process of notifying the approximately 87 million users whose data was harvested by the election consultancy Cambridge Analytica.

The social network eventually hopes to inform every user who was affected with a warning at the top of their Facebook news feed. For now, however, individuals can check by going to a new help page on the site or searching for “How can I tell if my info was shared with Cambridge Analytica?” in Facebook’s help centre.

Most users will see a message saying that “neither you nor your friends logged into ‘This Is Your Digital Life’”, the personality quiz that Cambridge Analytica used to gather its data.

Around 87 million individuals, including more than 1 million people in the UK, will receive a different response saying “a friend of yours did log in”. That means that their public profile, page likes, birthday and current city were likely shared with the company, as well as potentially the contents of their news feed at the time.

Around 300,000 people – including 53 people in Australia, 10 people in New Zealand, and an unknown number of users in the UK – will receive a message informing them that they installed the This Is Your Digital Life app. This means they almost certainly handed over the personal information of all their Facebook friends at the time, as well as formed part of the core group for the psychometric profiling that Cambridge Analytica carried out during the US election campaign.

Facebook has promised widespread changes to its platform to prevent further “abuse” of the sort it attributes to Cambridge Analytica. “These actions would prevent any app like [This Is Your Digital Life] from being able to access so much data today,” the company said in March.