Will the Swedish ‘say hi’ campaign work in London? We put it to the test

‘Unusual is what I thought’: a perplexed Simon Reichwald is greeted by Hannah Jane Parkinson. Photograph: Alicia Canter/The Guardian

Call it a defining modern day paradox; research shows that something many people have in common is … feeling alone.

Last week, the World Health Organization designated loneliness a “global public health concern”, as damaging to wellbeing as a 15-a-day cigarette habit. Whether caused by technology, economic circumstance or other factors, this “silent epidemic” is said to affect one in four of us.