Charity shops are vital to Britain's high streets because they boost local businesses and communities, according to a report.

Researchers for think tank Demos said the ­proliferation of Oxfam, Barnardos, Cancer Research and other second-hand fundraising stores encourages footfall and significantly reduces the number of empty premises.

The study challenges the perception that charity shops fuel high street decline. It found the shops help combat unemployment, with more than 80% of volunteers saying they were using their shifts as an opportunity to gain retail experience as a path to paid employment.

Charity Retail Association figures show the stores contribute to the economy by hiring 17,300 paid staff, with an extra 210,000 volunteers.

The Demos report also found charity shops helped tackle health and social problems, particularly social isolation, with the UK's ageing population.

In some cases shops act as service providers for their charities, offering advice and support for those in need.

Demos conducted a poll of 2200 members of the public, as well as about 150 charity shop managers and 150 volunteers.

One in five members of the public said they had met or talked to someone new in a charity shop, while 29% agreed they provided a sense of community and 28% said they encouraged different generations to meet.

Some 91% cited socialising and meeting new people as a benefit of volunteering, and 61% felt their volunteering led to improved health.