The elderly and blind should be given money to help buy digital TV equipment before traditional analogue TV signals are switched off, a report has said.
A new tick logo will denote digitally compatible equipment
The Ofcom Consumer Panel is advising the government on how to make sure the vulnerable are not left behind when the switch-off happens, probably in 2012.
The UK government may have to spend £250m-400m to make sure those groups can still receive TV, its report said.
Just 16% of over-75s had digital TV in 2003 compared with a UK average of 45%.
The report said the "most urgent" need was for a campaign to help socially isolated people understand what switch-over involved.
Colette Bowe, chairman of the Ofcom Consumer Panel, said: "Digital switchover will be the biggest challenge for people who have to cope with it on their own, without the help of family, friends or neighbours."
The body implementing switch-over, SwitchCo, should work with charities and local government to identify those who need help and give practical support, the report said.
"This will cost money. But it will be the key to providing the support that vulnerable people will need if they are to be helped to keep their access to television."
The government says it has already started a five-month campaign and a new "tick logo" will identify equipment that is digitally compatible.
Broadcasting minister Andrew McIntosh said switch-over must be a "truly inclusive revolution".
"There is still a divide between the digital haves and have-nots," he said.
"We want to create a genuine digital democracy, where everybody has the best possible access. This is why we need to switch off."