UK households have 1.7 billion items of clothing worth £30 billion that have been hanging unused in wardrobes for at least a year, a report has revealed.
Making more use of unwanted clothes could cut waste and the use of resources and unlock financial gains, the study on the impacts of clothing by waste reduction body Wrap found.
A third of all clothes bought end up in landfill, but if they were given to charities, local authorities or other organisations for reuse and recycling, they could be worth £140 million.
And increasing the time that clothes are used by nine months could reduce the water, carbon and waste impacts of clothing by 20% to 30% and save £5 billion in resources, Wrap chief executive Liz Goodwin said.
The average household has £4,000 worth of clothes in the wardrobe, but almost a third goes unworn for more than a year - most commonly because it no longer fits.
The report suggests people could make use of clothes for longer, by passing them to friends or family members, exchanging or sharing them, or they could sell them online or at local nearly-new sales.
New business models could also see retailers buying back their own brand clothes that consumers no longer want, which stores could then prepare for re-sale.
More than half the people surveyed by Wrap said they would sell back items and two thirds said they would consider buying returned clothes such as jeans or jumpers.
Ms Goodwin said: "The way we make and use clothes consumes a huge amount of the Earth's precious resources, and accounts for a major chunk of family spending. But by increasing the active use of clothing by an extra nine months we could reduce the water, carbon and waste impacts by up to 20%-30% each and save £5 billion.
"Consumers can realise the value of clothing by updating existing items for their own use, or selling or donating them for others to use. There are also significant opportunities for industry to capitalise on consumer interest and gain financially."