Businesses are keeping data safe in bunkers
The threat of a terrorist attack has seen businesses across the UK race to store vital information in underground bunkers.
A firm which runs a bunker in a former RAF nuclear shelter in Kent says demand has gone through the roof in recent months.
A L Digital says more and more companies are making contingency plans to safeguard computer files.
Many companies based in the World Trade Center went bust after the 11 September attacks because they had no way of salvaging lost data.
A L Digital's shelter - called The Bunker - is 30 metres below ground near Sandwich in Kent.
There has been a rise in demand lately because of 11 September
Paul Lightfoot, A L Digital
It has three-metre-thick concrete walls, steel doors weighing more than two tons and guards on duty 24 hours a day.
Companies can base their computer control systems at the site while continuing their day-to-day operations as usual at their office.
Operations manager Paul Lightfoot said the 11 September attacks made companies realise how important it was to back up their data and make contingency plans in case of loss.
He said: "11 September brought the point home to many companies and made them think long and hard about how safe their systems are.
"There has been a rise in demand lately because of 11 September, the Docklands bombing and now the latest threats."
It costs up to £36,000 a year to use The Bunker and Mr Lightfoot said hundreds of companies were using its services, with financial, medical and e-commerce firms the main customers.