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

Invitations line the fireplace, gifts are bought, hotels are booked. Now all you have to do is decide what to wear for this summer’s slew of weddings.

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

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

What is the size of your bag?

I would recommend avoiding carrying an oversized handbag that makes it look like you’re about to do your weekly shopping at Peter Jones.

You don’t want to have a giant tote sitting between your legs all day. I can get by with just a pocket in my pants.

What you want is a bag that’s discreet and pretty – one that can sit on the table during dinner, as a decorative item, or hang over your chair and look stylish.

The linen is out, the muslin is in

Be very careful with laundry. 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 your back will look like it crawled out of bed. It’s no coincidence that we never see the royal family wearing fabric that crushes.

If you’ve bought something particularly floaty, such as muslin, that doesn’t crease, take it to a major tailor and have it weighed. They can sew tiny weights into the hem of the skirt to make it hang more flatteringly – and reduce the chance of it blowing up in the wind to reveal your knickers.

You also need to consider the social impact of your sleeves. Draped sleeves are elegant but are a nightmare when it comes to the wedding breakfast or if the dishes are designed to be shared. You’ll drag all the excess tissue into your (and everyone else’s) food. Don’t let fashion take precedence over practicality.

The perfect hat height

Avoid wearing a hat that could obscure the bride’s view from other guests during the ceremony. I would also avoid a huge plume of feathers. It’s not ideal to kiss another guest and stick an ostrich feather up your nose.

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

If you are wearing a larger hat, you may have to agree to sit at the back of the ceremony, otherwise no one else will be able to see you.

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

Opt for a bejeweled headband or something smaller featuring a birdcage veil – something you don’t wear every day but won’t overpower the rest of your look or irritate other guests .

Heels versus flats

Guests should always check out the wedding venue online before risking destroying a pair of £1,200 Louboutins down a long gravel driveway. More than anything, shoes need to fit well; no gaping leather on the sides.

Cheap shoes will always gape when you wear them. Expensive, well-fitting shoes are not.

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

Your color code

It’s best to avoid strong colors like fuchsia pink or bright turquoise at a wedding, otherwise you’ll be unavoidable in every photo and no one will thank you for it. There’s a fine line between looking glamorous and smart and trying to steal the show.

It’s the bride’s day and you should never try to steal the spotlight. This remains the ultimate deadly sin. For the same reason, go easy on the shine. You want subtle embellishments at the cuffs or neckline.

Head-to-toe glitter makes it look like you’re reaching for the photographer’s lens and can be noisy when you walk. Heads should be turning toward the bride, not toward you rushing down the aisle.

Stick to a palette that works well with your environment. If the reception is in beautiful gardens, try flowers but avoid anything overwhelming. Subtle and elegant is always better than attracting attention.

Ban beach clothes

No rompers or playsuits, and definitely no shorts, no matter how tight they are. Save them for the beach.

And if you’re someone who gets really hot, my advice is to avoid silk. Any moisture there has a tendency to spread and will be very difficult to hide.

Instead, opt for a well-cut jumpsuit. Choose one in a special fabric – a jewel-colored brocade or velvet, without pinstripes. Or, palazzo pants are a chic alternative that will be equally appropriate in a ballroom, on the balcony of a country house or sipping champagne in majestic gardens.