@Daniel 1
You jest, but exactly this happened with their NTP time service a few years ago. Someone had an OpenBSD (I think) system (called Dougal if I remember correctly), sitting under a desk that was turned off, and their entire UNIX application farm lost their reliable time source (it may have been wider than this; I was only interested in the Unix servers). It was not spotted until NTP on the DNS servers (which were also distributing time as a peer NTP tier) started complaining about being unable to sync with their higher-tier time source after about 10 days.
Fortunately. the system was still present, and could be turned on again while they worked out how to remove it properly. Mind you, I was the local 'expert' on their NTP and DNS servers at the time, and I was a contractor. Says volumes about their own expertise, as I only have a passing knowledge of NTP. Think they use InfoBlox now, so I won't be doing that again.
I feel reasonably safe to talk about this now, as all of the people who may recognise me have since left Barclays when the Poole support centre was shut down. Still, black helicopters...