The Royal Crown Derby porcelain factory ramped down to a four-day workweek two years ago, stung by the casual dining trend and a flood of cheap china from, well, China. But a sudden rush of business has its production floor of 150 workers back on full-time schedules, cranking out more gilded baubles and collectables fit-for-doilies than at any point in the past three decades.

The 261-year old company’s financial white knight: Will and Kate, Inc.

The royal wedding of Prince William and Kate Middleton is shaping up as more than a dreamy moment for girls who long to be princesses or royalists keen on reinvigorating the genetic pool of the House of Windsor. The big day, according to the London-based marketing firm Verdict, is set to deliver a $1 billion jolt to the flagging British economy while ringing up hundreds of millions in longer-term gains as the couple rekindles global interest in the British royal family. Compare that to, say, Super Bowl XLV in Arlington, Tex., which generated a relatively paltry $615 million.

But what the royals giveth, the royals also drain away. And some Britons — particularly royal skeptics — are fuming at the April 29 wedding’s cost to the taxpayer. To be sure, Prince Charles, William’s father, will be footing the bulk of the undisclosed wedding bill with some help from the wealthy Middletons. But the British government will be covering substantial security costs. In addition, Britain will see a loss of productivity on a Friday in April that would not otherwise have been a national holiday.

But proponents insist that the wedding effectively heralds the return of a royal gravy train that seemed to have run out of steam after the death of Diana, Princess of Wales, in 1997. For the wedding itself, hotels and everyday Londoners have their eyes on the prize, hawking rooms ranging from $40 to $12,000 a night for the 600,000 onlookers that London tourism officials expect will flock to the capital for the event. That figure roughly matches the number who made the pilgrimage in 1981 to watch Charles and Diana in the opening chapter of their ill-fated fairy tale.

Kiss Me Kate beer is already on tap. Across Britain, shelves are filling up with the predictable bride-and-groom teddy bears shipped from far away factories in Asia, as well as the not-so-predictable Will and Kate refrigerator-freezers. Even Buckingham Palace is cashing in, peddling official royal wedding merchandise including frilly pillboxes and plates.

Since this is 2011, more than a dozen royal wedding apps are now available for download. And then there are the gambling parlors making a mint off royal bets. The firm William Hill is offering 38-to-1 odds that Prince Harry — the groom’s younger brother and best man — will forget to take the wedding rings to Westminster Abbey.

Yet for a wedding that many seen-it-all Brits are proudly declaring themselves profoundly uninterested in — one poll conducted for Republic, an anti-monarchy group, showed 76 percent “couldn’t care less” or were “largely indifferent” — sales of pricey, British-made products, from $180 loving cups to $19,000 commemorative clocks, are going so surprisingly well that companies such as Royal Crown Derby are seeing a 20 percent jump in overall revenue. That is on top of a surge in sales of frocks worn by Middleton and bought from mainstream London retail outlets, making them more accessible to the masses than the pricey designer dresses favored by Diana.

“What can I say?” said a beaming Bob Betts, managing director of Smith of Derby, a 155-year-old clockmaker whose first $19,000 Will and Kate clock sold off the shelf of a local department store within two hours. The stunned company, in this city 112 miles northwest of London, is now in the midst of producing at least 100 more. “When you see Kate walk into a room now, you can almost hear the ca-ching,” Betts said.

On the one hand, it suggests that some Britons may be closet royalists, sneaking home, under their fashionable Burberry raincoats, a Will and Kate enamel box that only a grandmother could love. Or that the grandmothers themselves are splurging.

But sales patterns also point to another major factor: The colonial appeal of the royal couple, who are driving an extraordinary wave of renewed interest in the British royal family in the United States, Canada, Australia, New Zealand and even Japan, China and Russia. Overseas customers account for roughly 40 percent of sales of Will and Kate memorabilia from Royal Crown Derby, for instance. But the biggest foreign buyers are Americans, who always seem to have time — and money — for a royal family they threw off nearly 235 years ago.

U.S. companies are peddling commemoratives, too — from replicas of Middleton’s sapphire and diamond engagement ring to Kate dolls by the Franklin Mint at $195 a pop. Thousands of Americans are expected to fly in for the wedding, though with just over four weeks to go, many London hotels have yet to sell out and are counting on a last-minute surge in bookings.

“It’s not quite like the presidential inauguration, where I was defending every room at the hotel months before,” said Anthony Stewart-Moore, general manager of Marriott’s Grosvenor House, London’s largest five-star hotel. He headed Washington’s Mayflower Hotel in 1993, when Bill Clinton was first sworn in. “But we are about 74 percent sold out already, and the booking window is going to close. . . . Who’s coming? Americans. But also Europeans and the British themselves. This is a big, happy day.”

Grosvenor House, like other London hotels, is trying to cash in on wedding fever. On the wedding day, their Middleton-themed “royal afternoon tea,” for instance, will be a banquet including scones with strawberry preserves from Middleton’s hometown of Bucklebury, followed by “Kate champagne cocktails” and cupcakes topped with icing in the form of her engagement ring, which formerly belonged to Diana.

With the queen’s 60th anniversary on the throne next year, a celebration known as the Diamond Jubilee, officials are hoping that renewed interest in British royals will bring a huge increase in tourism and continued sales of royal-related items. They note that tourism surged by 200,000 the year after Charles and Diana’s wedding.

But skeptics maintain that the House of Windsor is still a big drain on the British economy. They decry the wedding security costs to be borne by taxpayers at a time when the Conservative-led government is pressing ahead with historic budget cuts.

“As far as we’re concerned, we shouldn’t pay a single penny,” said Graham Smith, spokesman for Republic, the anti-monarchy group.

Scores of Londoners are vowing to use the holiday to fly to Spain or the south of France for a bit of R&R. Even that, though, may generate some much-needed revenue for airlines hit hard by the December snowstorms that embarrassingly shut down Heathrow Airport for days.

Yet some of those escaping the wedding chaos admit they will be glued to the TV. Antonia Windsor, 35, a freelance journalist, said she would be heading from London to the island of Jersey right before the big day.

“But,” she said, “I’ll be watching with grandma. She’s a big royalist.”

Special correspondent Karla Adam contributed to this report.