E-mail might just be responsible for the productivity increases that economists tell us are the key to rising prosperity. But it could also be sending us all mad.

The truth is that business is generally best done face to face, and if that is impossible, then speaking via the phone. But too many of us now hide behind silent, typed communications. The trouble is that the recipient of an e-mail does not hear a tone of voice or see a facial expression; nor can the sender modify their message halfway through, sensing that it is causing offence. When you read an e-mail you cannot tell the mood of the e-mailer.

A permanent written form is deadly if you are feeling impetuous and emotional. Too often I have made the mistake of sending an irritable response, which will have festered and angered the other end much more than a difficult telephone exchange. Spoken words fade; but e-mail is forever. I have learned that if I receive a really nasty e-mail – as I do occasionally about Channel 4 programmes, or a bad meal in one of my restaurants – then the best policy is simply to delete it immediately.

It is a rare week that I do not witness or participate in some foolish misunderstanding triggered by wrong interpretations of e-mail. Every so often, I vow to always call or meet people rather than send them electronic monologues (or perhaps diatribes). But convenience and laziness seize me, and I lapse.

It is so much easier to be tough via e-mail, or to get away with weak excuses, or to make things up, or to say no. Almost invariably, it is more human and serious to have a real discussion rather than a bizarre online conversation. I know employees who have been fired for sending abusive e-mails, or who have faced severe legal consequences for writing something they should have just said verbally.

Most of us are running our working lives like Richard Nixon ran the Oval Office – forgetting that the tapes are running. I recently had to chair a meeting and discovered monstrous microphones in the middle of the room, recording every word, which had apparently been the previous custom because of disputes about minutes. I insisted they were switched off, and the atmosphere lightened right away and became more conducive to open debate. I do not want to spend my time in a corporate version of the Big Brother house.

And, of course, everyone in business finds their inbox is almost swamped every day with spam. I notice I spend longer and longer sorting out the e-mails that matter from all the junk. It has become, I'm afraid, a dangerously corrupted medium. Large companies suffer chronic overuse of “reply to all”.

Moreover, e-mail can be a terrible distraction, especially if you use a BlackBerry. I was recently reprimanded for peeking at mine during a board meeting – a gross form of hypocrisy on my part, because I once threatened to sling out of the window any PDA-type devices being used in meetings I chaired. I have now vowed to switch off both BlackBerry and mobile in all meetings – anything less is uncivil.

It must be admitted that e-mail is hard to beat as a transmitter of documents and data. It forces the sender to carefully think through their arguments and express themselves logically. It allows you to reply swiftly to a host of different questions when time is short. You don't have to worry about journey times or travel costs, unreliable postage or engaged phones or voicemail.

E-mail is a marvellously economical tool for keeping in touch with far-flung commercial contacts; you can send them a note at your leisure, 24 hours a day.

It is also is a terrific method of discreetly and directly pitching to someone powerful. It certainly beats trying to get a meeting or even reach them on the phone.

Like it or not, I could not do my job without e-mail. Meanwhile, I know a senior financier, an ex-chair of a FTSE company, who still has his secretary print out his e-mails for him to read so he can then dictate replies for her to e-mail back. Now that really is mad.