LONDON >> France has the beret, America the humble baseball cap, yet Britain’s love of hats has always been in a different league.

Bowlers, baker boys, top hats, boaters, deerstalkers and countless ladies creations have been worn by royals and commoners alike through the centuries — a beloved tradition that will be in full force at Prince William and Kate Middleton’s April 29 wedding.

Bookmakers are betting on the color of Queen Elizabeth II’s hat — odds are on yellow — and the designer making the princess-to-be’s honeymoon headpiece. The salmon-colored tricorn hat that Princess Diana wore as she left for her honeymoon in 1981 spawned hundreds of copies.

"We’re British — hats are just what we do," Shirley Hex, a milliner who made hats for the queen, the queen’s mother and Diana, told The Associated Press. "Choosing the right hat is important for the person wearing it, but it’s also important for a designer. The right hat can make a career."

Theories abound on why Britain, compared to other European nations, became a country of mad hatters — an expression referring to the Alice in Wonderland character whose loopy persona was based on the many milliners who suffered neurological damage as they inhaled the mercury used to cure pelts.

Britain’s lousy weather might have contributed to the national obsession, but experts say it’s the royal family that has kept it alive.

"Hats have long denoted status," says Oriole Cullen, curator of a Victoria & Albert Museum 2009 hat exhibit that has since gone to Australia and heads to New York in September. "Up until the 1950s, a woman wasn’t even considered properly dressed unless she was wearing a hat and gloves."

The rebellious swinging ’60s and its variety of hair styles — along with the cramped confines of the modern automobile — prompted a steady decline in global hat sales, Cullen says.

Many blame John F. Kennedy — one of the first U.S. presidents not to don a hat — for hastening the demise.

In Britain, however, the tradition has stayed strong.

Royals have long been painted or photographed wearing hats — the Queen Mum had a special fondness for flouncy feathered creations, whereas her daughter has generally worn the same blocked style. Prime ministers and lawmakers, too, have been shown wearing top hats and tails at Oxford or Cambridge.

Britain is also home to the Henley Regatta, Royal Ascot and Lords — posh rowing, horse racing and cricket events patronized by royalty where hats are de rigueur.

And then there are the weddings and funerals.

Although the dress for William and Kate’s wedding will not be formal — invitations advise men to wear suits rather than top hats and tails — there will be a sea of ladies in hats among the 1,900 people invited to Westminister Abbey, much like the 1981 wedding of Prince Charles and Diana in St. Paul’s Cathedral.

Designers say some women began placing their orders when the couple announced their engagement in November. They advise clients to be original, focus on their outfits, forget about the price and don’t outdo the bride or royals.

Some creations by designers like Philip Treacy, who made two hats for the Dutchess of Cornwall when she married Prince Charles in 2005 and several other creations worn by Sex & the City star Sarah Jessica Parker, can cost more than 600 pounds ($1,000).

Treacy has been commissioned to do several of the royals’ hats for the wedding, as well as the bridesmaid’s headpieces. Hex, who taught the young Irish designer, said the pressure for an event like a royal wedding is extreme.

"I didn’t work for quite some time after Diana’s wedding," Hex, 70, says. "It nearly killed me."

Flight Lt. Al Conner, a pilot who helped train William and now flies alongside him on RAF search-and-rescue missions, is among 27 of the prince’s military workmates who will attend the wedding. He says the airmen’s wives have all been talking about the same thing: "What kind of hat is everyone else wearing."

Retail chains say sales of some hats and fascinators — usually smaller pieces attached to a comb or headband — are down due to the recession.

But in honor of the royal wedding — and to boost sales — London retailers will stay open for business on the public holiday. Associations have also encouraged their workers to don hats and fascinators during their shifts.

Specialty hat makers, meanwhile, say they’ve seen a slight increase in sales ahead of the wedding.

"There has been no recession in Mayfair," says Nicholas Payne-Baader of the James Lock & Co. Ltd, a hat company in one of London’s poshest areas that has supplied hats to the Duke of Edinburgh and Prince Phillip. "We’re making about eight hats for the wedding."