More than half of all TV sets in the UK still do not receive digital TV, according to media watchdog Ofcom.
The whole of the UK will be fully digital by 2012
Almost 31 million of the country's 60 million sets are not hooked up to any digital receiver, Ofcom has said.
But 25 million of those are secondary TVs in bedrooms or kitchens, with most main sets already converted to digital.
All TVs will need to be connected to Freeview, satellite or cable to keep working when the analogue TV signal is switched off between 2008-2012.
In total, 48.5% of all of the UK's TV sets received multi-channel TV at the end of 2006, according to Ofcom's latest Digital Progress Report.
But that rose to 78.6% when just main TV sets were counted.
19.6 million of UK's 25.3 million homes receive digital TV
30.9 million of UK's 60 million TV sets receive digital TV
Analogue switch-off starts in earnest with Border in 2008
Whole of UK to be fully digital by end of 2012
The most popular form of digital TV is Sky with almost eight million subscribers, followed by Freeview with 7.7 million Freeview-only homes.
More than three million households receive digital cable through Virgin Media.
The digital switchover is due to begin in earnest next year - but viewers in Whitehaven, Cumbria, will be the guinea pigs when their analogue signal is the first to be switched off later this year.
The date will be revealed by Digital UK, the body leading the switchover campaign, on Thursday.