Analogue sets will not work once the signal is turned off
Many people are still buying analogue TV sets unaware that they will soon need extra equipment to make them work, according to a report from MPs.
A parliamentary report claims that many viewers do not understand the implications of the digital switchover, despite a £200m campaign.
It says the digital tick labelling scheme for digital TVs is a "mystery" to many sales staff and customers.
Almost half of all TV sets sold in the first half of 2007 were analogue.
However, once the analogue signal is switched off completely those sets will not receive programmes without their owners paying for extra equipment.
The report did find the switchover timetable, which is taking place region-by-region until 2012, was on track to complete on time.
The report also criticises the government for "not taking adequate safeguards to secure value for money" in the digital conversion scheme.
It paid £803m of licence fee money to the BBC to deliver digital switchover, without ensuring proper accountability for the way the money is spent, the report said.
The Department for Culture, Media and Sport, and the Department for Business, Enterprise and Regulatory Reform has given the BBC responsibility for funding the public information campaign and delivering a digital help scheme.
But the report from the Parliamentary Committee of Public Accounts said the government departments have no means of holding the BBC to account.
Whitehaven was the first town to have its analogue signal turned off
Committee Chairman Edward Leigh said: "Many viewers do not seem fully to understand the implications of the analogue switch-off and are still buying analogue televisions - unaware that they have built-in obsolescence.
"The evidence is that the digital tick label, with which digital televisions are flagged in shops, is a mystery to many retail staff, let alone the people to whom they sell TVs."
He added that just 15% of households needed to make the switch to digital TV for their main set - but that left 26 million analogue TVs to be converted or replaced.
A Government spokesman said: "Digital switchover is progressing well and according to timetable. Take up continues to be high with 87% of homes having access to digital TV."
A spokesman for Digital UK said: "Some people may choose to buy analogue televisions for use with DVD players or games consoles.
"These sets do not become obsolete at switchover, as they can also be easily converted using a digital box, available from around £25."
Whitehaven was the first town to have its analogue signal turned off in October last year.