Women aged between 18-34, and so-called 'silver surfers' - i.e. web users aged 55 and over - are the most dominant group online in the UK, according to two separate reports.

Women in the 18-34 age group account for nearly one in every five (18 per cent) Britons online, research from net measurement firm Nielsen/NetRatings stated. They also spend the most time online, spending 27 per cent more time in front of the computer compared to men in the same age category.

Meanwhile, those aged 55 accounted for 22 per cent of UK visits to all categories of websites in the four weeks to 12 May, internet monitoring firm Hitwise said. This number was up by 54 per cent since 2005, and 40 per cent since last year.

Silver surfers are set to overtake 35-44 year olds as the demographic age group with the largest representation online, according to Hitwise.

Men vs women

"If you asked the question 'who spends the most time on the computer', most people would still answer 'men'," said Alex Burmaster, an analyst with Nielsen/NetRatings.

"This represents a seismic shift from the early days when the internet was the domain of the techno-geek."

The fact that new groups are emerging is the best illustration of how mainstream the internet has now become, Burmaster said.

Women in the 18-34 age category are primarily visiting websites dedicated to fashion, family, and lifestyle issues. The silver surfers mainly visited search engines, travel, news, and media websites.