Well as you can see the "Business" dress code was interpreted quite freely from the photo below.
|Dress Code : BUSINESS as interpreted by the Audience at a breakfast meeting in Summer of 2012|
At front stage :
The chairman of the Business Club was in a suit but without a neck tie.
The Government Minister and and the Civil servant were in suits and wore ties.
The Case study presenter was in smart casual with no tie and the social media team had a director in suit , shirt and no tie the rest of the team in company logoed T shirts - which looked great - but they were young and all had waists!!
Business Dress has changed considerably over the years in the UK.
Of course it depends .
So therefore it is best if possible to ask ahead but if in doubt remain 'suited and booted.'
After all if you are overdressed you can aways take your jacket off - just like I did at the breakfast meeting.