The UK had 20.275 million fixed broadband lines at the end of Q3 2011, according to the communications regulator.
Ofcom has made a downwards revision to figures published in the previous quarter, knocking off almost 200,000 BT DSL connections from the total reported in Q2.
As such, the number of UK broadband lines in Q3 was only slightly up on the 20.266 million reported three months earlier, despite strong growth.
BT Retail DSL lines accounted for 5,565,000 of the 20.275 million total, up from a revised 5,493,000 in Q2 2011.
Other DSL lines accounted for 2,601,000, down from 2,731,000 in Q2, and Virgin Media's cable services achieved 4,090,000 connections, up from 4,065,000 in the second quarter.
The number of 'other' fixed-line connections, including local loop unbundled broadband deals provided by the likes of TalkTalk and Sky, rose from 7,787,000 to 8,020,000 over the three-month period.
Last week, Ofcom reported that the average UK download speed increased from 6.2Mb to 7.6Mb between November 2010 and 2011.