A neutral campaign group should be set up to boost turnout in the European Union referendum promised by David Cameron, a think tank has recommended.
Senior figures on both sides of the EU debate welcomed the proposal, which is aimed at generating the same level of enthusiasm as the Scottish independence referendum, which saw almost 85% of eligible voters take part.
Under the plans, put forward by the independent British Future think tank, a so-called Third Campaign would be allocated free-to-air broadcasting slots during the referendum period with a specific focus on reaching groups who are traditionally least likely to vote.
Campaigners believe that a higher turnout will give greater legitimacy to the result of the referendum, which could be held this year if the Prime Minister secures agreement among EU leaders on his reform demands.
British Future director Sunder Katwala said: "The EU referendum will give Britons one of the most important choices in a generation. Yet many voters are undecided, unaware or simply not bothered.
"We think such a big decision needs a big referendum - one that engages as much of the country as possible in the choice we all have to make.
"A big referendum could be good for our democracy. It gives more legitimacy to the decision we make as a country - whichever way it goes, In or Out.
"We all saw the effect that Scotland's independence referendum had on its politics, engaging a nation and securing the highest turnout for any UK vote. A few people will also remember 2011's referendum on electoral reform - which few people noticed or took part in. It's clear which one we should be trying to emulate.
"The EU referendum is an opportunity to take politics out of the Westminster bubble and into people's town halls and front rooms. We shouldn't miss that chance."
A Third Campaign could be overseen by the Electoral Commission, with representatives of the rival Leave and Remain camps represented to ensure its neutrality.
British Future suggested that both sides could benefit from motivating typically apathetic sections of society - with younger voters thought to be more pro-EU while unskilled workers are believed to be more inclined to Euroscepticism.
Tory MEP Daniel Hannan, a prominent Eurosceptic, said: "I support this challenge for all sides to push for a high participation referendum. I hope the referendum becomes a kind of collective national festival, a celebration of our country's potential.
"We will win this campaign, not by convincing people that Brussels is corrupt, expensive or remote - for the most part, they're already convinced - but by offering something better."
Pro-EU former Tory MP Laura Sandys, chair of the European Movement, added her support to the proposal to boost turnout.
She said: "This referendum is so much more important than our general elections every five years - elections which are reversible. This referendum is about the long term future of the UK.
"It would be a bad day for democracy if this big decision is not taken by the largest number of citizens possible and the outcome would lose the necessary credibility that Remain or Leave need to take this country forward. We all have to make it our business to reach far and beyond the 'usual' voters or political actors to build a truly national and diverse debate."
The proposal is contained in a major new report on the EU referendum debate which will be published on January 6.