The trend leaves children unable to form proper friendships and to put more weight on the number, rather than the quality, of their online friendships, he said. That can, in some cases, lead to suicide, he said.

'They throw themselves into a friendship or network of friendships, then it collapses and they're desolate,' he said. 'But friendship is not a commodity. Friendship is something that is hard work and enduring when it's right.'

Nichols' comments come in the wake of a case in which a 15-year-old girl killed herself with a fatal overdose after being bullied on Bebo, a networking site.