Fig 1. Relationship between official and Flickr based estimates of visitors to the UK.

We analyse geotagged photos taken and uploaded to Flickr between 2008 and 2013. We identify users based in 28 countries outside the UK, and determine the average number of Flickr users who visited the UK from each of these countries each year during this period. We find a significant correlation between the detected number of Flickr users visiting the UK and the official estimate of visitors to the UK calculated by the Office for National Statistics (r = 0.86, N = 28, p < 0.001, Pearson’s correlation test). The solid line depicts a least-squares fit, and the shaded area represents a 95% confidence interval.