Business continuity firms were inundated with requests from companies last Tuesday as organisations faced the loss of telecoms and IT systems.
Shell's IT department in Manchester called on a disaster recovery plan, originally tested when WorldCom faced Chapter 11 bankruptcy two years ago, to ensure its networks continued to run.
"We had a disaster recovery plan which worked for us this time round, although communications are not 100% back to normal. However, our employees have not noticed anything out of the ordinary with the back-up communications network," said a spokeswoman.
The fire came on the day Computer Weekly reported that the Confederation of British Industry had called on the prime minister to alert businesses to the importance of proper emergency planning.
The incident has cost businesses in central Manchester alone an estimated £4.5m a day, with thousands of phone lines still out of action nearly a week after the event, said Manchester Chamber of Commerce.
Catering company Sodexho said the fire had a major impact on its offices in the North West. "We have been forced to suspend all non-essential IT activity," it said last week.
Co-operative Financial Services was forced to move 80 call centre staff from its Portland Street Street office to a call centre in nearby Miller Street where phone lines were still working.
The fire highlighted some embarrassing gaps in business continuity. The IT director of one UK-wide firm told Computer Weekly that its Manchester offices had failed to put any disaster recovery plans in place.
"We had one office in Manchester that was totally cut off," he said. "We have lessons to learn from not having a business continuity plan. We were lucky our phones were restored."
Flightdesk, the Co-op's direct travel arm, lost access to its internal Worldspan computer network, forcing staff to issue customers with electronic tickets or request them to pick tickets up from the airport.
Travelcare Direct lost access to its computer systems, but staff used the internet to obtain flight information.
First Option, a company that specialises in hotel and conference bookings in Stockport, said it only learned of the problem from reports in the media.
"We had a stock of emergency mobile phones on the premises and we hired extra mobile phones," said Ricky Kapoor, director of systems development.
"We could have invoked disaster recovery requirements by going out of the office, but we were able to conduct business through the internet and e-mail."