Say hi! Or just say bye Could the Swedish anti-loneliness drive work in London?

Call it a defining modern-day paradox, for recent research shows that something many people have in common is ... feeling alone.

- Hannah Jane Parkinson

Last week, the World Health Organization designated loneliness "a global public health concern", as damaging to well-being as a 15-a-day cigarette habit. And, whether down to technology, economic circumstance or other factors, this "silent epidemic" is said to affect one in four of us.

Now, the small city of Luleå in Sweden - a country of impeccably polite citizens, though not generally given to loquaciousness - has launched the Säg hej! (say hi!) campaign, with advertisements on buses and workshops in schools nudging residents into gentle bonding exercises. Åsa Koski, the municipality worker who came up with the idea, is adamant that even a simple hej from a stranger can make one "feel seen".