Getting shirty

Over the next couple of weeks I am attending a couple of conferences that ask for attendees to wear the nightmare 'Business Casual". What the hell is this really, some say it is just a suit without a tie, others take it to be trousers, shirt and a jumper and some go as far as jeans and a smart shirt.

I've been in need of some new shirts and have trusted Jermyn Street to tell me what Business Casual is and have bought four of their shirts which they tell me meet the criteria. Now, is it jeans or trousers...