“Do not speak to me when you see me. If I want to speak to you, I will do so. I want to save my throat. I don’t want to ruin it by saying hello to all of you sons of bitches.”

This memo to staff was written on January 13th, 1978, by a man who later acquired the label of the world's grumpiest boss. Edward Mike Davis was the founder and chief executive of Tiger Oil, and when he died last month his misanthropic letters were widely reprinted – allowing everyone to marvel at quite how grumpy he was.

Yet on reading his work, I was struck less by his grumpiness than by his excellent command of the genre. When it comes to getting a message across, Mr Davis set a standard that every modern chief executive’s email should be judged by.

Another of his masterpieces goes like this: “I swear, but since I am the owner of this company, that is my privilege . . . That differentiates me from you, and I want to keep it that way. There will be absolutely no swearing, by any employee, male or female, in this office, ever.”

Some of the content may be a little out of date. Science has proved that swearing at work is much to be encouraged as it makes people feel better – except when it is the boss swearing at an underling, in which case it makes everyone feel worse, and is probably illegal, too.

Brevity

Yet otherwise his style is perfect. It combines the four things needed in all communication from the top. The first is brevity. The memo forbidding employees from talking to him is a mere 42 words; better still, 39 of these have only one syllable.

The second quality is clarity. Even the stupidest or most distracted employee could understand his messages. It would be impossible not to. Third, he sounds sincere. Everyone knows exactly where they stand. And fourth, he picks an achievable goal and tells people how to get there.

Now compare this with what passes for decent communication in the corporate world in 2016. At about the time Davis was drawing his last breath, John Cryan was sitting down to compose the first of a monthly series of emails to Deutsche Bank's more than 100,000 staff in the hope of geeing them up to perform better in future.

I have picked on Mr Cryan as an example not because he is a bad communicator, but because he is considered a good one, often praised for his no-nonsense style. Yet the dying man would not have been impressed.

Missable news

Far from being brief, Mr Cryan’s message is 750 words long and starts with the random and missable news that the chief executive and his wife recently enjoyed listening to the Berliner Philharmoniker play some Mahler – before getting to the point.

Far from being clear, this was a muddle. The ostensible message was to tell staff to be more innovative, like Silicon Valley entrepreneurs. But at the same time he insisted that everyone must behave like their own risk officer – which is surely just the opposite. So which style does he want?

In practice it makes no odds, as neither result is achievable by memo. You can stop swearing because you have been told to by your boss. You cannot acquire the habits of an entrepreneur – or a risk officer – just because you’ve received an email telling you to.

Davis was a product of a more innocent age. Most of his memos were based around a central idea, spelt out in one memo: “You need the job – I don’t.”

Forty years later it is no longer acceptable to admit that power is shared unevenly – and that the boss has nearly all of it. This truth is taboo: instead all chief executives have to make the ludicrous pretence they are no more senior than anyone else.

Mr Cryan concludes with rank insincerity: “If my fellow members of the management board and I can be of assistance, please let me know.”

It is all very well for John Lewis – from which I am currently arranging delivery of an oven – to sign off its emails to me in this way. But Mr Cryan is chief executive of a big bank that he is trying to haul back to profitability. He should not be feebly wringing his hands Uriah Heep-style and putting out fake offers of assistance to his underlings.

He should have told staff briefly and clearly what he expected from them. If he ended up sounded a bit grumpy in the process, it would be a price worth paying.

– Copyright The Financial Times Limited 2016