The value of UK ecommerce transactions hit £408bn in 2009, excluding non-financial transactions, the Office for National Statistics (ONS) revealed on Friday.
This was almost 25% up on 2008, and represented 16.7% of all sales outside the financial sector, the ONS said.
Sales from websites rose 23.6% to £115bn, while the value of non-web online transactions (eg EDI) hit £293bn, 12% of all non-financial sales, it said.
The ONS, which compiled the figures from companies with more than 10 staff, said 76% had a website, but only 14.9% sold goods through it.
However, almost 52% (2008: 33%) used online networks to buy goods and services worth a total £466.3bn.
The ONS said just over 91% of businesses had internet access, and 87.4% connected using a broadband link. More than one-third (36.8%) used a 3G mobile connection. Some 6.8 million workers have internet access at work.
Two-thirds of public authorities and over 90% of large enterprises used the internet to interact with people, whose interaction with the authorities was mainly to gather information, the ONS said.
Over half of businesses - 50.7% - used the net to complete an administrative task entirely electronically. "Once again, it was the largest businesses that used this function the most, at 73.2%," it said.
Only 29.2% of businesses had a formal IT security policy that was reviewed regularly. Companies with more than 1,000 staff were four times more likely to have such a policy (85.8%) compared to firms with 10 to 49 staff (22.3%), it said.
Compulsory ICT security training was in place at only 14.5% of firms, but less than 2% of firms had downtime as a result of an external attack, it said. Less than 1% admitted they lost confidential data to intrusion, phishing or pharming attacks.
Almost 90% of large companies used an intranet to share information with staff, but the UK average was only 24.5%.
More large businesses than small ones took advantage of free or open source operating systems by 40.5% to 8.8%.