Les Binet and Sarah Carter get a little bit angry about some of the nonsense they hear around them… like the fact that heroes should be perfect.

Last month, we found ourselves at the centre of a heated debate. Our agency was casting for the hero of a new and, hopefully, long-running ad campaign, and the argument centred on what he should look like. The client was adamant that he should be a gym-honed, bronzed beach Adonis, sporting an impressive six-pack and just-enough facial hair. Weren't blokes all desperate to be like that these days? The creative team had other ideas. Their preferred bloke looked like he'd be great company to have a beer with. But Adonis he wasn't; more James Corden than James Bond.

We had to agree with the creatives on this one. Throughout history, from Odysseus to Princess Diana, all the great archetypical heroes have had 'lovable flaws' which draw us to them. Our heroes tend to be far from perfect – but they are all the more strong, engaging and alluring because of it.

A look at some of the rising politicians on both sides of the Atlantic shows the power of imperfection. On the right, we have Donald Trump and Boris Johnson, whose numerous gaffes seem only to enhance their popularity. And on the left we have Bernie Sanders and Jeremy Corbyn, grey-haired, slightly crumpled figures who seem to hark back to another era. On paper, none of them should stand a chance, but their flaws seem to make them more, not less, appealing to their followers.

So can imperfection be a source of strength? And if so, why? There are several reasons. First, it attracts attention. In a world of Identikit models, Kate Moss's crooked teeth and Cara Delevingne's strong eyebrows got them noticed and remembered. Second, it signals authenticity. Compared with the previous generation of slick, PR-savvy career politicians, characters like Trump and Corbyn seem refreshingly honest to their supporters, and, therefore, more trustworthy.

Third, it creates empathy. People who are flawed seem more like us, and so more likeable. The rise of Nigel Farage, the beerswilling, cigarette-smoking leader of the UK Independence Party, is surely due, in part, to his carefully crafted 'ordinary bloke' image.

And finally, imperfection can be aesthetically pleasing in its own right, as Dove showed in its Campaign for Real Beauty. The Japanese even have a word for this – wabisabi – a view that celebrates the allure of the imperfect and incomplete. The wobbly line, the cracked leather, the faded patina – all draw, rather than repel us.

Standout, distinctiveness, attractiveness, trust – these are all qualities that define successful brands. So maybe it's time for brand owners to embrace the power of imperfection. There are advertisers that get this, and their 'bravery' is rewarded by more powerful communications than their perfect, 'everyone looks awesome' adland competitors. Think of the Guinness Surfer with his odd eyes, the overweight construction worker pole-dancer in the UK's MoneySupermarket campaign, and the Southern Comfort 'whatever's comfortable' beach hero. Their imperfections draw us to them, the brands feel more authentic, and we trust them more because of it.

So where are the 'flaws' in the personality descriptors that we carefully choose for our brand definitions? We seem terrified to consider them – tying ourselves up in verbal knots and qualifications to avoid any possibility of a chink of vulnerability or imperfection. 'Aspirational yet accessible', 'strong but warm' – we've all written them haven't we? Get some negatives into your brand personalities please.

Back to that casting session. Who won the argument? Adonis or flawed hero? The creatives got their man. And the campaign is going down brilliantly.

So remember, imperfection sells. Our heroes are heroes because of their imperfections. Not in spite of them.