Broadband has been a political hot potato since 2008
The Conservatives have unveiled plans to deliver a "nationwide super-fast broadband", part of which could be funded from the BBC licence fee.
Shadow chancellor George Osborne said a Tory government would deliver speeds of 100 megabits per second (Mbps) to the "majority" of homes by 2017.
He said cabling in rural areas could be paid for by private investors, with the licence fee making up any shortfalls.
Labour accused the Tories of playing "catch-up" on broadband improvements.
The government has set a target that homes should have access to speeds of 2Mbps by 2012.
'Thousands of jobs'
Mr Osborne told the BBC's Andrew Marr Show: "In the 19th Century we built the railways. In the 20th Century we built the motorways.
"In the 21st Century let's build the super-fast broadband network that will create hundreds of thousands of jobs for Britain."
The Tories said money from private investors would pay for better cabling.
But it was added that it might not be attractive for private companies to install broadband cabling in some rural areas, in which case a proportion of the BBC licence fee could be used.
The Conservatives said the BBC could continue to set aside 3.5% of its licence fee - which currently goes to the digital switchover - to fund broadband expansion.
For Labour, Treasury Minister Stephen Timms said: "On broadband it's not Britain but the Tories that are playing catch-up.
"Labour have already announced measures for rolling out broadband across the country - and the Tories have opposed the plans to make that happen. "
The Liberal Democrats accused the Tories of operating "fantasy world economics".
"Anyone can promise the earth - what matters is how you pay for it," culture, media and sport spokesman Don Foster said.
"All independent research shows that the market simply cannot provide high-speed broadband in all parts of the country in the short term without investment.
"Hints that the license fee payer will be hit are the closest the Tories come to explaining how they intend to pay for this."
BT, which has a 25% share of the UK broadband market, said "going substantially further" to improve the country's network would require public sector support.
"We look forward to engaging with politicians from every party," a spokesman said.
A government report on the UK's digital future - dubbed Digital Britain - was published in June 2009.
The action plan included universal access to broadband by 2012.
The wide-ranging report also tackled internet regulation and public service broadcasting.