James Ashton: Setting a ceiling on relationships

At a breakfast event at the top of the Gherkin this week, Julia Hobsbawm set a new benchmark.

The upper limit for the number of meaningful relationships one person can maintain in business is 150, she said. Ms Hobsbawm, a former public relations partner to Gordon Brown’s wife Sarah, founded Editorial Intelligence to champion the power of knowledge and networking. If she can’t get beyond that magic number, then no one can.

More encouragingly, she says if work keeps you as active as it should, it’s hard to keep up a decent presence on more than two social media networks. So which to ditch: Twitter, Facebook or LinkedIn?