Plans to allow voters to use the internet to veto unpopular new laws are among radical constitutional reforms due to be debated at the Liberal Democrats' annual conference in Bournemouth next week.

Opponents would have up to 60 days to gather one million signatures for an e-petition requiring a referendum to repeal legislation.

The target is well within reach, as demonstrated by an online petition on the 10 Downing Street web site opposing a national road charging system.

Parliament would also be required to consider, and where appropriate act on, other petitions submitted online, and to formally debate the six proposals for new laws which secure the most signatures each year.

And an e-democracy centre would be set up to initiate and encourage the use of the internet to make all levels of government more responsive to democratic pressure.

The 'Giving Citizens a Voice in Parliament' motion is being proposed by James Graham, named 2007 Lib Dem Blogger of the Year for his Quaequam blog, and David Boyle, an author and former editor of Liberal Democrat News.

The motion goes considerably further than proposals from a Commons Committee which have secured the belated approval of government business manager and deputy Labour leader Harriet Harman for an e-petitions system, which is unlikely to be fully implemented before the next general election in 2010.

This would be limited to enabling Commons committees to consider e-petitions and decide whether to take any action and replace the current bureaucratic paper-based petitions process.

The Lib Dem proposals would involve a dramatic shift in Britain's unwritten constitution which contains no formal procedure for referenda and leaves parliament and the Queen with the final say on legislation.

The proposal was put on the agenda by delegates without the backing of the party leadership.

The conference is also expected to demand tougher protection for personal data, with a right for individuals "to opt out of government databases", endorse scrapping Labour's national ID card scheme, and call on the police to make greater use of handheld computers to cut red tape.