The first thing to bear in mind when the invite says 'smart-casual' is to aim for a look that is smart enough to get you in and casual enough to feel comfortable. "It's a look that sounds easy but is actually rather tricky to get right," says London-based stylist Ian Black. "However, it's a look that the English do better than anyone else so you have a headstart. Hugh Grant, Colin Firth and Guy Ritchie are all seasoned masters of smart casual, as are Princes William and Harry, who make it look effortless."

There are several staple items that should be in your wardrobe to readily adopt a smart-casual look. Chinos, cords, casual shirts, cashmere sweaters, polo shirts, smart jeans, loafers, brogues and a tweed blazer will never let you down. And of course to pull off the look correctly all clothing should be clean, pressed and not too shabby.

"When the invite says 'smart-casual' this doesn't mean no effort required," warns Ian Black. "Smart casual does not mean scruffy, so trainers are a big no-no, as are denim shirts, T-shirts (unless they're a polo) and tracksuits. Anything with a slogan on it is out of the question."

It's always best to avoid black - too formal - and opt for English countryside colours such as navy, bottle green, red and yellow. Getting the shoes right is essential with this outfit - too casual and you may appear scruffy, too formal and you'll ruin the look. Best to opt for a brown shoe style such as a brogue, loafer or deck shoe.

Stylist Ian Black reveals how to gauge the smart-casual temperature in some typical scenarios

The wedding reception
"For such an occasion I would tend to aim for the very smart end of smart-casual as it's easy to make yourself look more casual with a rolled up sleeve or hastily removed tie, whereas if you've underdressed you're pretty much stuck. A pair of smart jeans or cords, casual shirt and jacket matched with a classic brogue would be a good option. And of course always think about the couple themselves for a good gauge of just how casual they like things to be."

Dress-down Friday
"Overcome the temptation to turn up in your tracksuit just because you're let out of uniform for a day. Remember you're still a professional and should look like one. However, this is your chance to put a bit of your personality into your outfit. Keep it smart and unfussy. A pair of smart jeans or chinos and a smart casual shirts says, 'I may be dressed casual but my mind is still on the job.'"

Dinner with the boss
"This is your chance to impress - but be warned, don't overdo it. Your boss may not be thrilled if you outshine him or her - you should be looking to make a good impression without looking like you have gone to too much effort. Again a smart pair of chinos or jeans with a smart casual shirt is fine, maybe a tie depending on the restaurant and your boss. Just make sure everything is clean and pressed - and don't drop food down your front."

The sports club
"This is where things can get a little bit trickier, as each sport has a very different style when it comes to smart-casual so what would look fine in the sailing club wouldn't work in the golf club. As a general rule, all denim is barred, or at least frowned upon, from a sporting club - so wear chinos, cords or slacks instead of jeans. Polo T-shirts are appropriate and almost de rigueur .You can be slightly more casual as long as the items are good quality and a good brand. First impressions are especially important if you're trying to join - you need to look like you already belong to it!"