It was a breach of protocol few of the 2 billion viewers of the royal wedding would have noticed, but etiquette expert Alexandra Messervy noticed the faux pas immediately.

“I thought I was going to have kittens!” Messervy said of the moment the chauffeur pulled the queen’s car up to Westminster Abbey facing the wrong way. “You always let the queen out on the curb side, and she was on the street side,” Messervy said between sips of tea in the living room of her cozy cottage in Somerset, a rural county in southwest England.

Thankfully, the queen ignored the guard who opened her car door and instead scooted across to follow Prince Phillip out his curbside door.

As a member of the Royal Household of Her Majesty the Queen in the 1980s, Messervy should know. She helped plan the wedding of the Duke and Duchess of York (Prince Andrew and Sarah Ferguson) and also bought the queen’s Christmas presents, arranged lunches for U.S. presidents and made sure Buckingham Palace was run like a luxury hotel.

That explains why she is now in charge of English Manner, a British company that provides international training and consultancy in “contemporary etiquette, protocol, the arts, social skills and household and event planning” to high-net-worth individuals and corporations.

Founded in 2001 by Messervy, who is also the chief executive, the company mainly offers two kinds of training: hospitality etiquette (business and personal) and private estate and household management (educating domestic, hotel and yacht staff on everything from how to clean rare art to the importance of fluffing pillows).

And while confidentiality is promised to individual clients (including international entrepreneurs, royals, diplomats and various VIPs), the company’s corporate list is public and growing. Who knew, for instance, that such organizations as the Four Seasons and the Ritz-Carlton, as well as Barclays and the luxury label Champagne Bollinger would seek advice on topics such as shaking hands (no pumping) or eating a scone (gently open it in half)?

“What we are really teaching is confidence, both socially and professionally,” said Messervy, 51, whose résumé also includes working as the private secretary for Prince Michael of Kent, the queen’s cousin. “We teach traditional manners for today’s modern environment,” she said, explaining that the company’s students range in age from school- and college-age to international families and businesspeople. Whether they need to find a nanny, hope to join a charity board or need advice on how to dress or entertain, the English Manner is there to assist.

“When we first started the company, there was a lull in etiquette,” Messervy said. “It was considered almost politically incorrect to care about manners. But then, about four to five years ago, we started benefiting enormously from the fact that so many international people were coming to London to live and work. Those that sought us out wanted to learn how to better integrate into the culture.”

She added that many clients come from Eastern Europe, China, the Middle East and India. “They want to get in with the right people professionally and personally and be accepted,” she said. “But they also want their children to fit into the culture.”

“Probably, my hardest workday ever was trying to teach 24 4- and 5-year-old Chinese children the box step,” recalled William Hanson, 24, who often works in Asia as one of the English Manner’s full-time tutors. “I was sweating horribly,” he said of the two-hour Little Prince and Princess class, which (the cost is 295 pounds sterling, or $500) includes educating them on bowing and curtsying, table manners, thank-you notes and the importance of washing hands and standing up straight.

“I read my first etiquette book at 12,” said Hanson, whose collection of nearly 250 etiquette books includes his own. Last January, his “Bluffer’s Guide to Etiquette” was published in Britain. He is also a frequent etiquette guest on the British morning-talk shows and once did a humorous segment called “How Rude!”

Examples of the etiquette errors he highlights include smoking on the street, interrupting, not opening doors for women and dress-down Fridays. “It’s still a workday!” he said.

For Ngozi Princewill Utchay, chief executive of Artelier Lifestyle Consultants in Lagos, Nigeria, the course she took from the English Manner last March proved invaluable. It included lessons in deportment (walking with a book on her head; it fell off twice) to “netiquette.” (How to deal with cellphones? They should be silent and nowhere in sight except for an emergency.)

“We are in a commercial center here and do a lot of business with foreigners,” said Princewill Utchay, who runs a similar lifestyle-consulting company for Nigerians.