The deluge of email flooding workers' inboxes every day has become so overwhelming that it is now a 'broken business tool' in urgent need of fixing, companies have been warned.

The average employee spends an estimated 90 minutes to two hours a day wading through hundreds of messages, suffering interruptions and distractions with every ping from their PC or BlackBerry. Worldwide email traffic has now hit 196 billion messages a day, according to the research firm the Radicati Group, and is predicted to reach 374 billion per day by 2011.

Some organisations, such as worldwide accountancy consultants Deloitte and the publisher Cedar, have held 'No email days' to encourage staff to use the phone or talk to each other instead. But these are only stopgap measures.

'Email is a broken business tool,' said Jason Preston, new media manager at the Parnassus Group, a social media consultancy. 'There's been no innovation to separate the junk letters from the real ones.'

Tom Jackson, a senior lecturer in the information science department at Loughborough University, has devised a 'desktop PA' program which can prioritise relevant messages into a 'fast lane'.

Jackson, who has provided email training to clients including the Danwood Group and Leicestershire police, has also designed a program which can name and shame bad emailers within an organisation. 'It will go through all the emails you've sent and give you a score. It looks at how many people you sent it to, did you "reply to all", how big your subject line is, whether the message is well written. It gives a ranking of good and bad emailers, which can be a shock and make people reconsider what they're doing.'

Spam, the electronic equivalent of junk mail, has been estimated as making up nine in 10 of all emails sent. Although corporate spam filters can stop them, workers still find themselves blitzed by messages known as 'Bacn' because 'it's like spam but a little bit tastier'.