Summer tide of royal tat on the way after Jubilee logo is made free for all

The Queen's Golden Jubilee year is only two weeks old, and a multi-million pound souvenir free-for-all is about to begin in earnest – threatening to drown Her Majesty's celebrations in a sea of shoddy tat.

Buckingham Palace and the Home Office have relaxed many of their usual restrictions on royal merchandising, and have even provided an official logo for the jubilee, which is available for anybody to use, free of charge.

This has opened the gates to all manner of products, ranging from "official" royal vases and paperweights to comedy mugs and boxer shorts.

But while thousands of producers, manufacturers and retailers, not to mention the Inland Revenue, have been rubbing their hands with glee, experts are warning members of the public intending to squirrel away mementoes that they aren't going to make any money on them within their own lifetimes.

"When you get the big royal events, so much merchandise seems to be around," said John Sandon, head of the ceramics department at Bonham's auctioneers in London and an expert on BBC1's Antiques Roadshow. "Unfortunately, very little is of any real worth because so many millions will be produced. The majority of items from the Queen's Silver Jubilee have increased in value by inflation only. You can still pick up mugs from 1977 for a pound or two at a car boot sale."

Indeed, according to Mr Sandon, you have to go back as far as Queen Victoria to find jubilee merchandise worth anything. Mugs for her Golden Jubilee, which cost a few pence in 1887, can now fetch between £20 and £100.

As the nation gears up for the first Golden Jubilee since that event 115 years ago, experts are predicting the forthcoming months will see an influx of commemorative goods.

"Plenty of the lower end stuff is available already, but the higher end of the market will start to appear in the next few weeks," said Steven Jackson, secretary of the Commemorative Collectors Society. "As the June celebrations approach, the more light-hearted and humorous goods will also start to arrive." Shoppers can already buy a number of items, ranging from plates and postcards to bunting and special house bricks.

In 1977, goods worth more than £630m were produced to celebrate the Queen's Silver Jubilee. This year's merchandise is already worth an estimated £105m.

The freedom afforded to manufacturers by the ready availability of a central logo means that it will be hard to keep track of all the hundreds of official items on sale when the celebrations begin in earnest. The simple emblem, in black and white to facilitate all kinds of reproduction, represents a crown with the words "The Queen's Golden Jubilee – 2002", and was designed by Nicholas Jenkins, who also produced the Silver Jubilee logo.

Yesterday, his business partner, Roland Wells of Design Connection, voiced his concerns over the lack of control enforced over the use of the logo: "The image is going to be on everything from flags at street parties to quite sophisticated products like glassware," he said.

"Our view was that it should have been more disciplined than it was, but the Palace and Home Office didn't want to be dictatorial about it. It's the Queen's emblem, but I suppose the question is, do we own her or does she own us?"