Tessa Jowell wants protection for "vulnerable" consumers

The government had hoped the analogue signal would be switched off by 2010 but this has now been revised.

Ms Jowell said following discussions with broadcasters, including the BBC, 2012 was now a more realistic target.

She said consumers must be given clear information about the changes and what is available to them.

New BBC director general Mark Thompson had already indicated the corporation would be ready for the switchover by 2012, although he added it could reach the original 2010 target if necessary.

In a written statement, Ms Jowell said broadcasters had not reached a full consensus but that the BBC had suggested setting 2012 as a target.

But some areas could be affected as early as 2007 as regions become testing grounds for digital TV.

And two villages in south Wales, Ferryside and Llansteffan, are set to take part in a trial which should see their analogue TV signals turned off next year.

"We believe that switchover should be broadcaster-led but that the final decision on timetable should balance these benefits against the need to ensure that the interests of the most vulnerable consumers are protected," Ms Jowell wrote in a statement submitted to Parliament.

The BBC has indicated it will take a "special responsibility" for persuading people to invest in the digital future, which would be through satellite, cable or digital TV through an aerial via Freeview.