The number of unbundled lines in the UK stood at almost six million last month.
According to figures from the Office of the Telecommunications Regulator (OTA2), there were 5.9 million unbundled lines at the end of May 2009.
The statistics show that there are 5.87 million wholesale line rental lines, while the number of telephone numbers using carrier pre selection is 3.97 million.
As noted by Ofcom, the number of unbundled lines was just 123,000 in 2005, so the recent figures reveal a dramatic increase in the last four years.
The telecoms watchdog pointed out that a greater number of unbundled lines is good news for both consumers and businesses.
Prior to the creation of local loop unbundling (LLU), broadband services could only be obtained from BT by most people.
However, as a result of the introduction of LLU, "millions of homes and small businesses have switched to providers other than BT", Ofcom said.