I’d just finished interviewing a heart-broken widow. As I packed up my tape recorder and notebook I felt sorry about leaving her to an empty afternoon of stirred up memory. I said, ‘I’m about to have lunch. Could I tempt you to join me?’ She declined politely. Then, as she was showing me out of the door she added quietly, ‘It’s just that I’ve always preferred men.’

I was mystified. Then, fifty yards down the street, I caught sight of my reflection in a shop window. There I stood, six feet tall in heels, wearing a trouser suit, shirt – and tie.

Very early that morning as I was getting ready to catch the London train, my fashion-conscious daughter was critical of my sartorial effort. I vaguely recalled her saying Dolce et Gabanna (or some such) had decreed the tie was in – as she’d threaded one of her father’s round my reluctant neck. In the ensuing rush I’d forgotten all about it.

There was no point in retracing my steps to tell the widow I didn’t normally dress like a man. I could only reflect that the tie carries all sorts of messages, true and false. What we wear sends signals to those around us about who we are, and sometimes about what we think of them.

Robert Peston, the BBC’s economics editor, learned a similar lesson when he turned up at a press conference in China to interview the Chancellor of the Exchequer. He didn’t wear a tie which provoked a storm of criticism. He was already being attacked for the unruly length of his hair. Now he was being told off for showing disrespect to George Osborne.

One commentator put the offence on a par with Jeremy Corbyn failing to sing the national anthem. "He is a BBC journalist representing the British population, addressing the second most important person in Government. It’s basically doing the fingers up without saying it."

At the core of the comment is a fundamental misunderstanding of the role of the journalist. Certainly basic respect is due to the Chancellor – as it is to any fellow citizen. But it must be delivered sparingly. It should not tip into deference because that works against the journalist’s ability to ask an awkward question; to push to the point of rudeness when answers are withheld.

But what about seriousness? Did Peston failing to wear a tie undermine his standing as economics editor because it showed a certain frivolousness? Some people seem to think so. But not Peston himself.

At the Radio Times festival last weekend, he was unrepentant. "I think the notion that what makes you a serious journalist is wearing a tie is bonkers."

Is he right? Does it matter what we wear to work so long as we remain within the bounds of decency?

Generally with dress codes, there should only be one rule: that the clothes people wear shouldn’t interfere with their ability to do their jobs. For doctors, say, or even journalists like Peston, that extends to clothes that don’t undermine the seriousness of the subjects they are discussing.

Not wearing a tie doesn’t come close to doing that. For doctors, a tie might even get in the way or be unhygienic.

There are exceptions, of course: the very talented, the powerful and the charismatic tend to write their own rules.

Steve Jobs lived in a black polo neck jersey and jeans. Mark Zuckerberg, founder of Facebook, still dresses like a student. Nelson Mandela wore a flowery shirt-tunic to Buckingham Palace.

Barack Obama left his tie off when he went to greet the Chinese president. In 2013 David Cameron encouraged the members of the G8 to dress more informally saying it would make it easier "to get things done". He thought a more relaxed atmosphere would be more conducive to working better together and focus on what really mattered.

The bosses at the BBC have a different concern. A presenter, they insist, should never distract from the news. In other words, they should never become more talked about than the story they are telling. And yet, don’t we absorb the news more effectively when the person delivering it is a voice we trust. I’d trust Peston on the economy tie or no tie.

Dress code is a security blanket as well as being a mistaken mark of status at society gatherings like Henley Regatta or that annual explosion of bling at Ascot. It’s also very important at Edinburgh’s New Club. There a jacket and tie is de rigueur at all times except in certain rooms. By contrast the Glasgow Arts Club states on its website that no dress code applies. Members are invited to relax in a laid-back atmosphere.

I know which I find more appealing.

There can of course be no rational reason why a strip of fabric knotted around the neck should change either ability or respectability. The wearing of it is a demonstration of conventionality; of team spirit and of conforming. Sometimes the pattern on the tie signifies membership of a particular club, school or institution. I’m no expert but I’m told the stripes of such ties go from left shoulder to right side. When Brookes Brothers were introducing striped ties to their collection they took care that the stripes fell the other way.

It’s laughable really. And yet, each of us when we waken tomorrow morning will go to the wardrobe and make a choice; just as we previously went shopping to choose what is in the wardrobe. If we put on a shell suit we will send one message about ourselves that will speak about our income, education, and likely address; if it’s red corduroy trousers, a middle-aged man will send another that will include political affiliation.

So when we turn up to a meeting the clothes we choose are speaking for us. And this is the nub of the criticism against Peston. The open-necked shirt is potentially saying, "Don’t forget that you’re no big cheese. Don’t forget I’ll still be an opinion-shaping broadcaster when you are out of office." Could it also be saying "I’m the star here. Rules are for other people"?

And is that what we all do when we turn up inappropriately dressed? If we wear jeans to a party or a posh frock to a barbecue, are we putting our-selves, our choices above those of our hosts?

I don’t think so.

Surely what matters is our demeanour.

Take for example Alexis Tsipras, the Greek prime minister. He attended his own formal swearing in without a tie. I can’t imagine he meant to insult his country or its people. And here Labour leader Jeremy Corbyn struggles to wear one with conviction, even on the most formal of occasions.

Both are serious men. Their tie-lessness signals their non-conformity, not disrespect or casualness. And in Peston’s case it also signals that he’s outside any establishment – which is exactly the place for a serious journalist to be.