Falling foul to a cyber attack would cost one in 10 UK businesses up to £1m, according to fresh research by BAE Systems.
The poll of 100 business leaders from private sectors firms with more than 1,000 employees also showed that the average cost of a cyber attack was at least £330,000.
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More than half of those surveyed said that they had suffered a cyber attack in the past year, while a fifth said they did not know or were not confident that they could return to business as usual within 48 hours of such an event.
Julian Cracknell, managing director for UK Services at BAE Systems applied intelligence, said: "The research confirms that cyber security is no longer merely a technical issue, but a challenge for the board.
"Businesses need to ensure they have the right people, process and tools in place, so when a major incident occurs they are equipped to understand, contain and remediate. If action isn’t taken immediately, the price of cyber ignorance – for the company and the wider economy – could be severe."
It coincides with the launch of the UK's national cyber security centre (NCSC) tomorrow which aims to bring together expertise on these issues.
The NCSC will be based in London and headed by the current director general of cyber at GCHQ, Ciaran Martin.
One of the its first tasks will be to work with the Bank of England to advise the financial sector on how it can better manage cyber security risks.