A neutral campaign should be set up for the forthcoming EU referendum to help generate the same level of enthusiasm seen during the Scottish independence poll, an independent think-tank has recommended.

Under plans put forward by British Future, a so-called Third Campaign would be allocated free-to-air broadcasting slots during the referendum period with a specific focus on reaching groups which are traditionally least likely to vote.

Campaigners believe that a higher turnout would give greater legitimacy to the result of the referendum, which could be held this summer if David Cameron is able to get agreement among his EU partners on his reform demands.

"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,” said Sunder Katwala, the think-tank director.

"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.”

He went on: "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,” declared Mr Katwala.

He added: "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.

Tory MEP Daniel Hannan, a prominent Eurosceptic, said he backed the push for a high participation referendum, hoping it would become a “kind of collective national festival”.

He added: "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, chairwoman of the European Movement, added her support to the proposal to boost turnout, saying it would be a bad day for democracy if such a big decision was not taken by the largest number of citizens possible.

“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."

Elsewhere, Lord Baker of Dorking, the former Home Secretary, has become the latest senior Conservative following Lords Howard and Lawson to call on David Cameron to suspend collective ministerial responsibility for the referendum on Britain’s EU membership, saying unity within the party would fracture if MPs and ministers were whipped to support the Prime Minister’s view.

He said: “If Tory MPs and ministers are whipped to support the Government line to stay in, then the broad church would fall apart.

“Tory whips would start twisting arms, begging or bullying recalcitrant MPs to persuade them to vote against their own convictions; in effect, to lie in public. This would create a storm of bitterness which would crystallise for a very long time the split in the party,” he added.