The information requested falls within the responsibility of the UK Statistics Authority. I have asked the authority to reply.
Letter from Karen Dunnell, dated March 2009:
As National Statistician 1 have been asked to reply to your recent Parliamentary Question asking how many homes in the UK have an internet connection installed. (260347)
In 2008, an estimated 16.5 million UK households had Internet access. This represented 65 per cent of UK households and an increase of 1.2 million households since 2007. These are the latest estimates available. This information is taken from the annual First Release on Internet Access 2008, published in August 2008. The Interviews to compile this information took place over January to March 2008.
The First Release is available via this link:
The 2009 First Release will be published later this summer.