Online UK consumer spending is expected to hit £39bn a year by 2010, new research has claimed.

The report by global payment firm PayPal estimates that there will be 24.9 million UK web shoppers in 2010, a rise of 71 per cent compared to 2005.

The most lucrative online shopping sector in 2010 is set to be food and groceries which will account for an estimated £6.24bn representing a rise of 235 per cent on 2005.

Clothing and footwear will be worth £2.27bn , an increase of 160 per cent on today. Online sales of electrical goods are expected to grow substantially to £4.6bn, an increase of 136 per cent.

This market is one where substantial sums are likely to move away from the high street, according to the report.

However, the study goes on to warn that thousands of small businesses are in danger of falling behind and missing out on valuable profits from e-commerce.

PayPal estimates that one in five purchases in the UK that would not have happened on the high street will take place online by 2010, accounting for a further £3.2bn.

Carl Olav Scheible, head of merchant services at PayPal, said: "Over the past few years we have seen the internet gradually eating away at the high street.

"Consumer interest in broadband has been a key driver for the emergence of 'convenience home shopping' with 10 million UK households now signed up."