If you're impressed with the inexplicably long hours your colleagues have been putting in over the past couple of months, ask them what they've been up to. They may be part of the growing number whiling away the small hours playing computer games such as Doom, a virtual-reality shoot-'em-up game of extreme violence.
Bankers say that the real fun starts when they link up through their firm's internal network to spend hours shooting each other in what is called a death match. Fun for them, but it could bring their house down because the games take up so much memory.
At one stage the problem had got so out of hand at the London offices of SBC Warburg Dillon Read that an e-mail circulated telling people that if they didn't stop playing Doom the network would melt down.
Addiction to Doom is so widespread that it has convinced one banker to resign his job as vice-president in fixed income at JP Morgan to set up a company which organizes death matches and other virtual reality experiences.
In his seven years working at JP Morgan and Citibank, Paul Flanagan found that many of his colleagues were arriving early and staying late to play games.