Figures released by the Office for National Statistics (ONS) show that the value of internet sales rose to £71.1bn in 2004, 81% higher than the previous year's total of £39.3bn.
Overall, 6.7% of firms sold their goods and services over the internet last year, compared to 5.4% in 2003. A further 35.3% of companies made purchases themselves via the web, totalling £62.4bn. This is up from 29.4% in 2003.
The ONS study also showed strong growth in the number of firms using new technology, with rises in those creating web sites and using broadband internet connections.
Some 33.8% had a web site last year, compared to 30.7% in 2003.
Meanwhile, some 42.3% of businesses incorporated broadband as their primary internet connection, a huge jump from the quarter of firms, which used the technology in 2003.