In the thick of storm season, lightning can strike small firms twice: in productivity and on the bottom line, a new study warns.

Last year the Tornado and Storm Research Organisation (TOSRO) recorded 300,000 lightning strikes across the UK, which connectivity solutions provider Belkin estimates can cost the nation's PC owners a collective £24 million, based on the average cost of PCs and the loss of one computer with each strike.

Along with computers, every piece of electrical equipment is at risk from lightning-induced power surges, Belkin warns. All essential office equipment, from printers to fax machines to copiers and mobile storage devices can be irreparably damaged, and all data lost.

The costs can be huge, both in lost working time and expenses paid to replace the damaged equipment, especially for small and start-up businesses or those who operate their business from home.

Such businesses may not have had the time or money to protect themselves from Mother Nature.

"A power surge is one of those things that we like to think only happens to other people," said Robin Falconer, sales and marketing director at Belkin UK.

With the numbers of recorded strikes on the rise, that attitude could change.

The Met Office recorded 5,271 lightning strikes between 11 and 15 July. Its detection system has been known to pick up 130,000 lightning discharges in a single day.