Watson Wyatt was able to maintain services when its London offices were evacuated in June 2007 after the partial collapse of a nearby building, but found some areas of the plan that needed improvement.
The business continuity plan provided for some employees to move to a workplace recovery centre provided by SunGard Availability Services and others to work remotely from home, but many found collaboration difficult, said Vijay Bains, risk manager for Watson Wyatt in the UK.
"Before the incident we were pushing ahead to get as many people as possible working from a remote location, but after four days more people were asking for a seat at the recovery centre so they could work with their teams," he said.
The company's revised business continuity plan makes provision for more people to use its workplace recovery centres in future if necessary.
Bains said last year's incident had shown that a more blended approach to business continuity was better than a single approach centred on remote working to allow greater flexibility.
The revised plan also makes provision for alternative venues for events scheduled to take place at the company's offices during any future disaster recovery period.
"As a result of last year's incident, we had to cancel a lot of presentations because there was not enough room at the recovery centre for the size of seminars we had organised and we could not reschedule them at short notice," said Bains.
Another important lesson learned, he said, was that business continuity was not only about technology, but was also about people and it is important for planning to take that into account.
He said although Watson Wyatt had a detailed plan in place last year, the company realised that there was more that could be done because business continuity was not only about getting people behind PCs, but also involved looking at all activities in the business and how they worked together.
Watson Wyatt, which has 7,000 staff in 32 countries, plans to get certified on the new British standard BS 25999 for business continuity by the end of 2008.