Image copyright Getty Images

Burberry, the upmarket British fashion label, destroyed unsold clothes, accessories and perfume worth £28.6m last year to protect its brand.

It takes the total value of goods it has destroyed over the past five years to more than £90m.

Fashion firms including Burberry destroy unwanted items to prevent them being stolen or sold cheaply.

Burberry said that the energy generated from burning its products was captured, making it environmentally friendly.

"Burberry has careful processes in place to minimise the amount of excess stock we produce. On the occasions when disposal of products is necessary, we do so in a responsible manner and we continue to seek ways to reduce and revalue our waste," a spokesperson for the company said.

The FTSE 100 company said last year was unusual as it had to destroy a large amount of perfume after signing a new deal with US firm Coty.

As Coty would be making new stock, Burberry had to dispose of £10m worth of old products - largely perfume.

Over the past few years, Burberry has been working hard to make its brand exclusive again after it went through a phase when counterfeiters were "sticking the Burberry check on anything they could", said Maria Malone, principal lecturer on the fashion business at Manchester Metropolitan University.

Destroying unwanted products is part of that process, she said.

"The reason they are doing this is so that the market is not flooded with discounts. They don't want Burberry products to get into the hands of anyone who can sell them at a discount and devalue the brand," Ms Malone said.

Image copyright Getty Images Image caption Burberry has been trying to make its brand more exclusive

Burberry is not the only company having to deal with a surplus of luxury stock.

Richemont, which owns the Cartier and Montblanc brands, has had to buy back €480m (£430m) worth of watches over the last two years.

Analysts say some parts of those watches would be recycled - but much would be thrown away.

Environmental campaigners are angry about the waste.

"Despite their high prices, Burberry shows no respect for their own products and the hard work and natural resources that are used to made them," said Lu Yen Roloff of Greenpeace.

"The growing amount of overstock points to overproduction, and instead of slowing down their production, they incinerate perfectly good clothes and products.

"It's a dirty secret of the fashion industry. Burberry is just the tip of the iceberg," she said.

Fashion paradox

Tim Jackson, head of the British School of Fashion at the London campus of Glasgow Caledonian University, said luxury fashion firms such as Burberry faced a paradox.

To satisfy shareholders, they have to keep expanding even if that risks "diluting their identity and creating excess stock", he said.

"There's no way they are ever going to solve this problem."

Last November, Burberry announced a revamp intended to "re-energise" its products over several years.

That includes taking its brand further upmarket, closing stores that are not in "strategic" locations and creating a "centre of excellence" for luxury leather goods.

It has also cut costs, which has helped boost profits.

In Burberry's most recent financial year to 31 March, the company reported a 5% rise in profit to £413m, with sales little changed at £2.7bn.