Why you should NEVER wear bright colours, silk dresses or feathered hats to a wedding, by celebrity wedding planner JOHNNY ROXBURGH, who reveals the secrets to the perfect guest outfit

The invitations are for the mantle, the gifts are bought, the hotels are booked. Now all you have to do is decide what to wear to summer weddings.

Who better to advise you on the many fashion pitfalls to avoid than socialite wedding planner Johnny Roxburgh, who has organized weddings for the rich and famous and personally attended hundreds of them.

Here he explains the colors to avoid, the best size for your hat and handbag – and a trick that will make any dress more flattering.

How big is your bag?

I would advise you to avoid carrying an oversized handbag that looks like you are doing your weekly shop in Peter Jones.

You don’t want a giant bag sitting between your legs all day. I manage with just one pocket in my pants.

What you want is a bag that is discreet and beautiful – a bag that can sit on the table during dinner, as part of the decor, or hang over your chair and look stylish.

Linen is out, chiffon is in

Be very careful with linen. You really need to think about how you will get to the wedding and how long you will be sitting in a car. Too long and the back of you will look like you just crawled out of bed. It is no coincidence that you never see the royal family wearing a fabric that crushes.

If you have bought something particularly liquid in, e.g. chiffon that doesn’t crease, take it to a great tailor and get it weighted. They can sew small weights into the hem of the skirt so that it hangs in a more flattering way – and reduces the risk of it lifting in the wind to reveal your knickers.

You also need to consider the social impact of your sleeves. Draped sleeves look elegant but are a nightmare when it comes to the wedding breakfast or if the dishes are designed for sharing. You will draw all the excess substance through your (and everyone else’s) food. Don’t let fashion overtake practicality.

The perfect hat height

Avoid wearing a hat that may obscure other guests’ view of the bride during the ceremony. I also wanted to avoid a giant feather plume. It is not ideal to kiss a fellow guest and get an ostrich feather up their nose.

Choose a style that is no wider than 18 inches and no taller than eight inches. Ideally, it should also be one that can be worn at an angle so that others can easily access you for a kiss.

If you are wearing a taller hat, you may have to accept that you sit at the back of the ceremony or no one else will be able to see.

You can’t wear a tiara if you’re a guest at an afternoon wedding…unless you’re actual royalty or the event is white tie and evening.

Choose a jeweled headband or something smaller that has a birdcage veil – something you don’t wear every day but won’t overpower the rest of your look or annoy other guests.

Heels v flats

Guests should always check the wedding venue online before risking ruining a pair of £1,200 Louboutins on a long gravel driveway. More than anything else, shoes must fit properly; no gaping leather on the sides.

Cheap shoes will always yawn when you walk in them. Expensive shoes that fit well do not.

Go as high as you want with the heels, but you have to be able to walk in them. And if the reception is on a lawn and you’re in stilettos, of course you sink. I’d much rather see nicely decorated apartments that still look special and show that you’ve made an effort.

Your color code

It’s best to avoid strong colors like fuchsia pink or light turquoise for a wedding, otherwise you won’t miss every single photograph and no one will thank you for it. It’s a very fine line between looking glamorous and smart and trying to steal the show.

It’s the bride’s day and you should never, ever try to stage her. It remains the ultimate cardinal sin. For the same reason, go easy on the spark. You want a subtle embellishment at the cuffs or neckline.

Head-to-toe sequins look like you’re looking for the photographer’s lens and can be noisy when you walk. Heads should turn for the bride, not you rustling up the aisle.

Stick to a palette that works well with your surroundings. If the reception is held in beautiful grounds and gardens, try floral motifs, but avoid anything overwhelming. Subtle and elegant are always preferable to attention.

Banish beachwear

No rompers or playsuits, and absolutely no shorts, no matter how tailored. Save them for the beach.

And if you are someone who gets very hot, my advice is to avoid silk. Any moisture on it tends to spread and it will be very difficult to hide.

Choose a well-cut jumpsuit instead. Choose one in a special fabric – a brocade or jewel-toned velvet, no pinstripes. Or palazzo pants are a smart alternative that will look equally appropriate in a ballroom, on a country house balcony or sipping champagne in stately gardens.