The queue of people who will line up to see who can scream loudest probably starts with the police national computer (PNC) which would probably go offline for a month if it lost its ISDN links (says my source) - which sounds unlikely, because last time I looked it was a pitifully small system, capable of handling well under 1,000 simultaneous enquiries. But that's what I heard, from people who should know.

It goes on. The Driver Vehicle Licensing Authority (DVLA) still uses bags of ISDN connectivity. As indicated above, so do several military centres, and if I tried to tell you which ones, I'd probably be exiled to Malta and given a 1200bps Hayes modem as my only link to the World Wide Web, so I won't.

Now, the question several people are trying to answer is a simple one: "Why on earth are all these people using an obsolete technology?" Part of the reason is exactly the reason why BT would quite like to get rid of it - it is uncontended (i.e. no one has to share it) data bandwidth with very low latency, but (for what it is) incredibly cheap. People look scornfully at its 64 kilobit by two channels bandwidth of 128 kb/s and laugh. What they don't see is that you get that 128 kilobits all the time, without packets being dropped and without contention from grockles doing bittorrent uploads.