Not to mention you'd also destroy pretty much every non-military (ie very seriously rad-hardened) satellite which didn't have the Earth between it and the nuclear device.

So, a large area of Earth based elecronics destroyed, and even if you've managed to avoid that, no communications or Earth observation satellites to aid in recovery.

(...and yes, most satellites are built with rad-hard components, but they're not designed to withstand an EMP, which requires substantially more shielding).

Across town could be 20 miles away in London. On the other side of the Thames is very likely to have it's power and data coming from completely independent systems, even a different power station and over a different part of the national grid.

Since BT was historically the only telecoms provider, even now they are plenty big enough to easily be in a position to have multiple independent data feeds, and if they all fail, nothing else in the capital is working anyway, so a DC's survival would be a minor issue.

A six hour drive from London going North would almost put you in Scotland, and in the other direction, you would have run out of land, and be well on your way to Paris if you crossed the Channel.

gmack said:
Actually the quote from Ecclesiastes is "The love of money is the root of all kinds of evil." The missing word is quite significant. For some reason it's one of the most often misquoted scriptures.

...and is apparently often misattributed as well, since that quote comes from Timothy 6:10, not Ecclesiastes.