Few mid-sized businesses in Britain have made provision for staff to work from home in the event of disruption or disaster, and less than a third have updated their business continuity plans since the attacks on London in July.
Research commissioned by Cable & Wireless has found that while two-thirds of companies admit that their business would be materially impacted if staff were unable to access the office for a day or less, more than six out of 10 (62 per cent) are not equipped to enable staff work from home.
In the event of being shut out, few employees would have access to the corporate network or even a list of contact details for their colleagues and clients.
To make matters worse, the survey of 100 IT managers at mid-sized UK firms (30-500 employees) found that almost four out of 10 (38 per cent) of companies either don't back up their data or - crucially - only keep data at their main office site.
If their building was destroyed or became inaccessible, they would lose data and information vital to the survival of their business.
More extraordinarily, London lags behind the rest of the UK's mid-sized businesses in being prepared for disruption.
While almost two-thirds (63 per cent) of mid-sized organisations claim to have business continuity plans in place, in London this falls to only a third.
In other words, in the face of a major public transport disruption or disaster, many companies would be unable to stay open for business.
"With business continuity, it pays to be pessimistic – whilst large enterprises are more aware of the risks, small to medium businesses need to wake up and make preparations fast," Said Mark Hanvey, Cable & Wireless' chief security officer.
"As the research shows, many businesses aren't even backing up data off-site – a simple and cost-effective means of protecting against data loss and ensuring business survival.
"The technology now exists to allow staff to easily work from home as if in the office simply by plugging into a broadband connection. But an alarming number of small and medium businesses are failing to plan for when offices can't be accessed or for network failures."
And as he pointed out, according to government research, four out of five businesses affected by a major incident close within two years, rising to nine out of ten for those that lose data.
Jim Norton, senior policy adviser at the Institute of Directors, which supported the research, said that all firms – regardless of size – needed to think through the implications of major disruption
"You cannot legislate for every event, but directors do have a responsibility to develop contingency plans. We are calling for businesses to take business continuity planning in all its aspects, technology, people and processes, very seriously.
"That may mean backing-up data off-site, having access to alternative facilities, and giving employees the technology to work away from the office.
"Business continuity planning is an important part of the day job. Companies shouldn't be complacent and investment shouldn't be put off until next year, next month or even next week."