LulzSec letter
The letter LulzSec posted on its Twitter page.

Just after the hacking collective LulzSec issued a statement via email to the U.K.'s NHS warning the service that its online security and networks were out of date and vulnerable to cyber attacks, it has been revealed that the London Ambulance Sevice (LAS) suffered a massive software failure this Wednesday.

The reports specified that the LAS's -- which is part of the NHS -- systems went down on Wednesday forcing the service back to the bygone days of pen-and-paper record keeping.

The failure happened after the service attempted to replace its 20-year-old system with a new one. The old system was only restored yesterday, leaving operators no choice but to register emergency calls on paper during the outage's one-day duration.

Since the outage an LAS spokesman commented on the system failiure via a post on the service's website.

"We have now reverted back to our original call taking computer system and are responding to 999 calls as normal,

"We took this decision after we experienced technical issues implementing a new 999 computer system yesterday morning (8 June)."

The LAS has not yet commented whether it will resume its efforts to upgrade its systems, nor has it specified what specifically caused the system to crash during the upgrade process.

The news comes just after the hacking collective LulzSec issued a warning to the NHS via email that its network and systems were out of date and vulnerable to cyber attacks.