Commemorative plates, towels and tea bags are vying for attention in shop windows near Buckingham Palace, ready for the first coronation of a British monarch in 70 years.

"We've ordered about three times more (memorabilia) than usual," Sardor Zok, a salesman in charge of coronation merchandise at online souvenir retailer Cool Britannia, told AFP.

Mr Zok expects demand to rise as Charles III's crowning approaches on Saturday.

Elsewhere, the coronation has presented an obvious marketing opportunity.

The upmarket department store Fortnum & Mason, which supplies the royal family with its tea, is selling a special organic coronation Darjeeling for the coronation for £19.95 ($24.90) per 200 grams.

"We chose Darjeeling because we understand that King Charles drinks this with a spoonful of honey," said Ottilie Cunningham, one of the brand's managers.

"We decided to only select organic tea gardens in Darjeeling due to His Majesty's passion for organic agriculture."

Ceramics company "Emma Bridgewater", popular with royal collectors, has produced a wide variety of tableware for the occasion ranging from £12 to £28 for a mug, tea or coffee cup.

All of its pieces are hand-decorated, the manufacturer says, adding that sales have started off on a high note and are expected to be better than for Queen Elizabeth II's Platinum Jubilee last year.

The coronation will also see sales of some six million coins and medals minted for the event, millions of pounds worth of jewellery, flags and banners as well as 10,000 teapots, according to forecasts by consultants the Centre for Retail Research.

The cost-of-living crisis will take a back seat, with Britons and tourists expected to spend more than £245 million on souvenirs alone -- and more than £1.4 billion if the wider celebrations are included, it added.

'Fanatic'

"Lots of people buying souvenirs will be older people... less affected by the cost of living crisis -- they own their houses, have a pension," said CRR director Joshua Bamfield.

In the souvenir shops behind the palace, customers come in to browse an eclectic mix of royal memorabilia, looking to spend "£15 to £20", according to store manager Ismayil Vadakkethil.

The items include protective gloves embossed with the royal coat of arms, Union Jack decorated paper towels and streamers and a "monarchy forever" T-shirt featuring the king.

"My mother is a fanatic royalist, she's got a glass cabinet with all of these royal things," said Australian Julie Whitehead, 63.

"So I'm going to pick up the King Charles ones for her because her cabinet is full of Queen Elizabeth ones," she added.

But while King Charles items sell well, so do souvenirs featuring the monarch's late mother, who remains very popular with royal souvenir hunters.

"I prefer the queen," said Amélie Zerr, a 40-year-old French tourist, adding she was looking for a "small, kitschy souvenir" and had her heart set on a mug and a coaster.

The customers have changed in recent times, Mr Vadakkethil has noticed.

"Recently I've noticed that it's not just tourists coming in. People who work next door, in the offices, the Londoners themselves, they come into the shop," he added.

For Britons, "it's a big event", and many will be experiencing a coronation for the first time, said Bamfield.

"People will be impressed by the ceremonial aspect and buy things to remember it," he predicted. "It's part of the British psyche."