This week BT is expected to connect its five millionth broadband customer.
Downloaders could be driving the take-up of broadband
The milestone comes a year ahead of the telecoms company's own predictions and includes broadband connections sold on by third party firms.
Lower prices and higher speeds forced by strong competition among broadband suppliers are thought to be behind the sustained growth in faster net access.
The figures suggest that soon more than half of all net users in the UK will be on a broadband connection.
Higher and higher
The five millionth customer will be connected by BT Wholesale, the arm of the company that re-sells fast net links to BT and many other telecommunications companies.
The five million customers are shared among the 200 companies that re-sell BT lines. BT's own broadband business has a 35% share of these high-speed users.
In a statement, Ben Verwaayen, chief executive of BT, said: "The momentum of broadband is continuing to build."
Prime minister Tony Blair, welcomed the announcement and said that broadband was of vital importance to everyone in the UK.
He said: "Broadband has the ability to transform the way we live our lives - whether in business, education or in how we use our leisure time."
"Most significantly of all," he said, "the adoption of broadband technology will enhance the UK's ability to compete in the modern knowledge economy."
In the last four months BT said it had connected up one million people to broadband.
This stands in stark contrast to the early days of high-speed net access in the UK as, according to government figures, it took about two years to sign up the first million.
BT said that, by the summer, 99.6% of British homes will be connected to exchanges that can provide fast net access.
The main factor that has sustained interest in broadband is thought to be its sharply lowering price.
"Historically broadband has been priced at a premium over dial-up, but increasingly that's not the case," said Ian Fogg, broadband and personal technology analyst at Jupiter Research Europe.
Broadband leaves your phone line free for others
"It's not a case of why get broadband but why not?" he said, "The price difference is either small or has ceased to exist."
Although the numbers of people playing games online, downloading music and movies is growing, so far, said Mr Fogg, this is not thought to be driving take-up.
People switch to broadband for very basic reasons, he said.
"It's about speed, not blocking the phone line and always on connections," he said.
The fact that last year BT reduced the cost of getting access to its exchanges so rivals can offer cheaper fast net services has also boosted numbers.
Despite this, according to the Office of National Statistics, more people still go online via slower dial-up connections.
Although the number of dial-up users is on a slow decline, in January 2005 59% of all net connections were dial-up.
But with fast net connections growing at 5% per month, broadband will soon be the dominant method that Britons use to go online.
As well as the five million broadband customers connected via BT, there are thought to be more than two million people going online via cable connections from Telewest and NTL.
Mr Fogg said BT's announcement was more about past achievements that the future.
"The speeds available are very poor compared to other parts of Europe," he said.
Mr Fogg would like to see BT set new targets that commit to getting a proportion of customers on to higher speeds by fixed dates.
"It's a reflective release rather than one that's forward looking," he said.