Visits to the BBC News website rose sharply as people went online to find out more about the bomb attacks in London last Thursday.
Londoners are returning to the Tube following the attacks
The site had a record estimated 115 million page views, more than five times the average daily figure.
Other UK news sites also saw a surge in visitors after the attacks.
The BBC was the most popular destination, followed by Sky News and the Guardian newspaper site, said web monitoring firm Hitwise.
"At times of crisis, people turn to the BBC News website as their first port of call, for fast reliable updates and the context they need to put the story in perspective," said Nic Newman, head of editorial and technical development at the BBC News website.
The BBC News website (news.bbc.co.uk) generally coped well with the greater than usual number of visitors.
Contingency plans to cope with significant events involve using the cacheing network of technology firm Akamai.
Akamai has a huge number of servers dotted around the net that hold copies of popular webpages. On Thursday, almost all the BBC News website pages were handled by Akamai.
Traffic to the site hit record numbers, with an estimated 115.7 million page impressions on Thursday.
Interest in the bombings continued on Friday, when the BBC News website recorded 53.7 million page views.
These figures compare with a typical weekday when the site receives around 23 to 25 million page impressions.
The top story was the main report on the attacks, which had 15.3 million page views. The previous record was 2.3 million for the result of the US Presidential election last year.
There was also a big jump in the number of people watching or listening to video and audio material from the BBC, with the site registering some eight million requests.
Demand for news
"Averaged over the 24-hour period, we had to deal with five times our normal traffic levels," said Mr Newman.
"At the peak, about lunchtime on Thursday, we were dealing with 10 times the normal level of activity - about 40,000 hits per second.
"It was a considerable technical challenge, and for almost everyone, we managed to deliver our news webpages more quickly than on a normal day."
The figures reflect the findings of Hitwise, which said that BBC News accounted for 28.6% of all news page impressions in the UK on Thursday.
Traffic to the BBC homepage made up a further 6.42%. Sky News was third with 3.8%, and Guardian Unlimited fifth with 2.4%.
The Guardian said it had 7.8m page views on Thursday, its highest ever.