Maybe wear like a shirt with dark jeans and some nice shoes?
smart-ish jeans, maybe dark, long sleeved shirt with the top button undone and some smart shoes, its not over the top but still looks smart....
dark trousers, tee - shirt and a jacket
maybe dark jeans, plain white t-shirt and a dark blazer?
Shirt and tie anyway mate. Show them you value their time of the day and that the interview actually means something.
Same scenario with me the other week for a College course I was applying for. The letter I had told me it was an informal interview but I went in with shirt, tie waistcoat and other appropriate clothing. Doesn't hurt to make an effort in my opinion.
Trousers and shirt. End of.
dark jeans, top and jeans with a casual jacket
Suit - no tie. however casual the office is, I bet they still dress up for meetings. Your interview is a meeting with a senior guy.
shirt not tucked in, with trousers, and no tie, with smart shoes got me a job lol,
Shirt, tie, trousers and maybe a V neck jumper.
Could go without the tie if you want to be more casual.
No such thing as a casual interview unless its for collecting glasses down at your local dive.
Absolute minimum - Shirt and trousers.
I'd go with a suit. The guy who said not to dress to smart isn't the one interveiwing and tbh, if someone come to an interview I was giving not dressed smartly it would make a bad impression and first impressions matter.
Dress smart casual and if you see them all in suits just politely say sorry and say you were told to dress casually. They will most likely just laugh anything off.