It is said that clothes maketh the man. I would go further than that and say clothes also set a state of mind.

I constantly bang on about the importance of making the right impression in a job interview, which definitely includes wearing appropriate attire. The number of candidates we’ve turned down for arriving in tracksuit bottoms and a pair of trainers doesn’t bear thinking about.

But it’s more than just making a good impression and portraying the right image expected by the person you’re meeting, it is also about establishing the right attitude and, to use a well-worn cliché, show that you mean business.

There has been a lot of debate about whether the BBC’s economics editor Robert Peston, who is soon to swap channels for ITV, has been dressing too casual for his TV appearances.

Peston has declared the idea that presenters should wear a tie to appear professional as “bonkers”. He has adopted a style to make him stand out from the crowd, which he believes he is entitled to have because of what he’s achieved in the media.

However, that shouldn’t need to be the case. You can have a strong persona and still be dressed sharp. And keep your mind sharp too.

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This week I took part in a number of radio interviews to discuss my resignation from Business for Britain over its change of position on Europe.

I joined the group to support its campaign to scrap the 50p tax rate, but I have always believed the UK should stay in the EU. When the organisation announced it would be spearheading the Vote Leave group I had no choice but to follow my principles and resign.

My phone was red hot as you can imagine and as well as speaking to LBC and a few others, the opportunity to explain my reasons came up on BBC Radio 4’s Today Programme. I had to be in the studio at the crack of dawn and it would have been easy to turn up in jeans and a T-shirt. After all, it’s 6.30 in the morning and who can see me on the radio.

Of course, that was never going to be my attitude. I was suited and booted when I walked through the door of the BBC. Feeling smart and business-ready helped me in an interview on a complex subject.

It’s an approach I’d encourage all business owners to take. There has been a cultural shift in what is acceptable business attire in recent years, influenced by the chino-wearing tech guys from Silicon Valley, but I still believe a suit and tie makes the best impression and focuses the mind.

I wouldn’t have confidence in an accountant who turned up to a meeting in shorts and flip flops and I certainly wouldn’t be happy to put my central heating system in the hands of a plumber in dirty jeans and a ripped t-shirt.

Relaxed dress tends to produced relaxed attitudes and as BBC Radio 4 Today programme presenter Justin Webb recently wrote in the Radio Times, ‘dressing down can lead to major sloppiness’.

It’s common sense, but as we know, that isn’t always that common!