My first BlackBerry, an 857 model that I bought second-hand on Ebay in 2001, had a 16/20-line monochrome display, could only handle wireless e-mail and data and ran for a week on a single charge. I loved it.

Since then Canada’s Research in Motion has signed up almost 20m BlackBerry subscribers, and I have upgraded at least half a dozen times as new models have come along.