It was also found that the average insurance claim for a theft from a garden in 2007 stood at just under £300.
Neil Laird, home insurance manager for Sainsbury's, said that the findings demonstrated that people "need to take care to protect their homes".
He added: "Homes seen to have 'rich-pickings' that are left unsecured, may be targeted again so as well as tightening up security, it's worth picking a home insurance policy that allows you to benefit from and protect your no claims discount."
Earlier this year, research by Nationwide claimed that one third of people in the UK value their garden contents at between £250 and £1,000.
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