The most popular thing to buy in secret for both sexes is clothes, followed by DVDs, music and gadgets such as mobile phones, the research from fairinvestment.co.uk suggests.
People living in London were most likely to keep purchases secret from their partners, while those living in Yorkshire and Humberside were least likely to splash the cash on the sly.
Fairinvestment.co.uk spokeswoman Rachael Stiles said: "As the UK heads towards a recession there is a chance that secret spending between partners may increase, as when money is tight we are less likely to own up to spending money on non-essentials like a new handbag or perfume."
Meanwhile, Ugg boots, the celebrity fashion staple are stomping towards the male market.
The company is now trying to convince American men that they too can emulate celebrities such as Brad Pitt and Justin Timberlake in the sheepskin boots.
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