UK broadband will hit 21 million by the end of 2012 despite slowing growth rates, according to research.

Almost 600,000 lines were added in the third quarter of this year, considerably lower than the million-odd connections added in the peak periods of 2006, says analyst Point Topic.

Take-up is slowing as the pool of dial-up users switching to high speed internet access shrinks. But growth will remain steady as use of broadband becomes ubiquitous and the popularity of social networking sites increases.

In five years' time, 73 per cent of homes and 85 per cent of businesses will have high speed internet access.

"We forecast that about 4 per cent of the remaining households without internet access will convert each year," said Point Topic chief analyst Tim Johnson.

"That is roughly the average for the past two years as a whole, but much better than in the last few quarters - so it implies improved performance by the industry," he said.