BT has confirmed that some of its broadband customers — both wholesale and retail — suffered outages for several hours last night.
The telco said the glitches, which affected users between 1630 and 1930 (both GMT), were due to a software problem linked to user authentication.
Three servers were the cause of the problem, which impacted users randomly around the country, according to BT.
A BT spokeswoman said the outages resulted from increased congestion on the network which prevented fresh users logging on, although those already connected via BT's broadband network will have experienced no interruptions to their service.
BT wouldn't provide details of which of its retail customers were affected as a result, although AOL, Virgin, Wanadoo and Zen all confirmed they had been hit by outages.
Although none were immediately able to provide precise information on how many end users experienced problems, a Zen spokesman described the outages as "short-term but significant" and a spokesman for Wanadoo said most ISPs had been touched by the problems at BT.
AOL, however, estimates that the number of its users who may have experienced problems with their Internet connectivity could be up to 100,000. "It's a pretty busy time of the day," a spokesman for AOL said.
BT's spokeswoman said that the telco has launched a "full investigation" into the problem.