Small businesses are the weakest link in the UK's fight against e-crime, according to the Conservative Party.

Speaking at the National Hi-Tech Crime Unit's (NHTCU) second e-Crime Congress, Jim Paice, shadow minister for home, legal and constitutional affairs, told delegates that despite high security spending among large enterprises, small businesses could provide a back door into corporate IT networks.

Small businesses and the 2.6 million sole traders operating in the UK constitute 99 per cent of the country's firms and 40 per cent of its workforce.

"Large companies have more money to invest in security, but small businesses are often part of their supply chain," said Paice.

"Insufficient security measures by small businesses not only present a risk to themselves, but also to large firms."

The shadow minister warned that half of small businesses suffer a security infringement each year.

Bernard Frieder, director of emerging technologies at the office of the e-Envoy, confirmed to the congress that, in addition to installing new security technologies, companies needed to look closely at the policies they have in place governing network usage.

"We need to examine how we set up our networks and who we let in and out of them," he added.