The number of UK companies infected by malware has fallen by 60 per cent over the past two years, according to a survey by PricewaterhouseCoopers (PwC), on behalf of the Department for Business, Enterprise & Regulatory Reform.

But for two-thirds of the companies affected, malware caused their worst information security breach of the year. Spyware now accounts for one in six of the worst infections, suggesting attacks are becoming less frequent but more sophisticated.

Companies have become aware of the threat of viruses, according to PwC partner Chris Potter.

"If there is one area of security where UK plc has really got the message, it’s virus protection. Only a tiny minority of companies don’t take this area seriously," he said.

Only 14 per cent of UK companies reported a malware infection last year, down from 35 per cent two years ago when the last survey was carried out.

Less than half of very large businesses had an infection last year.

Corporate anti-virus defences have significantly improved, the survey found.

Ninety-eight per cent of firms have software to scan for spyware, up from 75 per cent two years ago.