It was so much safer in the slow old days. After a sleepless night, you rose in anguish to pen a farewell missive, wounding the once beloved with bitter, hurtful words. Or else, your fevered brain emboldened by brandy, you poured out your confession to your employer, ready to face the blame and the consequences. Alas, there was no dispatch rider to bear away the fateful message. And when, in the morning, you were sealing the envelope, remorse set in. You repented your haste and tore up the letter. Employer and inamorata remained untouched by your ire.

How technology now traps the impetuous! With one small click, a torrent of abuse is spread across the recipient's screen. Bridges are burnt, vendettas declared and lives for ever unhinged by fate. So Google's offer to spare you from your inner self by rejecting any command to send an e-mail after midnight or during a heady weekend unless you can first prove your sobriety with answers to a few quick sums could prove a godsend. Except for the maths. What if you cannot calculate? That urgent acceptance of a job offer will never get sent. Or, if you are an Einstein, even the toughest equation would not prevent dispatch of a risky billet doux.

There must be other methods of restraint. Mobile phone makers have already invented a built-in breathalyser to prevent late-night drunken calls. The phone or the computer could block selected numbers in the address book. Auto-prompts could ask you, earnestly and often, if you really meant to send the e-mail. How about a gadget to censor unsavoury language? Most of all, we need a button to prevent the opening of abuse sent in awful error to the wrong recipient.