Facebook's population in Britain has reached 27 million, representing more than two-thirds of the country, according to the latest figures.
The data, which comes through Nielsen, shows that 19 million people have accessed the social network through a mobile device.
Globally, Facebook has around one billion users who make some 3.2 billion "likes" or comments every day.
The news comes just as Facebook is to launch Retail Centre, where retailers can get tips and advice on how to maximise the platform to engage with customers.
UK Facebook users are among the most active in the world too, spending around seven hours each month online, which accounts for a fifth of all their minutes using the internet.