UK businesses are more vulnerable to a disastrous loss of IT systems than ever before, according to a new report by PricewaterhouseCoopers.

The survey found that 58 per cent of UK businesses would suffer significant business disruption if their IT systems were not available for one day.

PwC said that this is the highest percentage since the surveys began, and that the figure is as high as 70 per cent for larger companies.

"There has been an explosion of information within businesses," said Martin Sadler, director of the Systems Security Lab at HP Labs Bristol.

"Acquiring, analysing and delivering the right information to people so they can act on it is a major challenge for companies.

"The volume of data, and companies' dependence on it, poses significant backup challenges."

The survey found that 28 per cent of companies still do not have a disaster recovery plan, despite 92 per cent of respondents describing it as an 'important IT issue'.

Half of those companies that do have a plan have not tested it, making the probability of failure much higher.

The survey did have some good news, however. Critical data was backed up by 99 per cent of companies and 86 per cent do this on a daily basis.

Some 85 per cent of the companies that do back-up critical data take those backups offsite (up from 76 per cent two years ago), which is crucial if a key business is destroyed.

Chris Potter, a partner at PwC, said: "It is encouraging to see that almost every UK business makes backups, and the vast majority now take these backups off-site. The risks are well understood, and it does not take an incident to raise awareness.

"The number of companies with a disaster recovery plan has gone up. However, experience shows that plans are only effective if regularly tested. It is a concern that only half of plans have been tested in the past year."

London is no longer the leader in disaster recovery planning, according to the survey results.

Businesses in the South West now make more disaster recovery plans than anywhere else in the country, possibly because of last year's flooding.